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        <figure class="highlight sql"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span class="line">116</span><br><span class="line">117</span><br><span class="line">118</span><br><span class="line">119</span><br><span class="line">120</span><br><span class="line">121</span><br><span class="line">122</span><br><span class="line">123</span><br><span class="line">124</span><br><span class="line">125</span><br><span class="line">126</span><br><span class="line">127</span><br><span class="line">128</span><br><span class="line">129</span><br><span class="line">130</span><br><span class="line">131</span><br><span class="line">132</span><br><span class="line">133</span><br><span class="line">134</span><br><span class="line">135</span><br><span class="line">136</span><br><span class="line">137</span><br><span class="line">138</span><br><span class="line">139</span><br><span class="line">140</span><br><span class="line">141</span><br><span class="line">142</span><br><span class="line">143</span><br><span class="line">144</span><br><span class="line">145</span><br><span class="line">146</span><br><span class="line">147</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">create</span> <span class="keyword">database</span> employee</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp;</span><br><span class="line"><span class="keyword">delete</span> <span class="keyword">from</span> emp <span class="keyword">where</span> empno=<span class="number">9999</span>;</span><br><span class="line"><span class="keyword">select</span> ename,sal <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> sal &gt; <span class="number">2000</span>;</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> deptno = <span class="number">20</span> <span class="keyword">and</span> sal &gt; <span class="number">2000</span> ;</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> deptno = <span class="number">20</span> <span class="keyword">or</span> sal &gt; <span class="number">2000</span> ;</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> sal <span class="keyword">between</span> <span class="number">1000</span> <span class="keyword">and</span> <span class="number">3000</span> ;</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> empno = <span class="number">7788</span> <span class="keyword">or</span> empno = <span class="number">7369</span> <span class="keyword">or</span> empno=<span class="number">7521</span>;</span><br><span class="line">&lt;!---more---&gt;</span><br><span class="line"><span class="comment">-- in</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> empno <span class="keyword">in</span>(<span class="number">7788</span>,<span class="number">7369</span>,<span class="number">7521</span>);</span><br><span class="line"><span class="comment">-- DISTINCT 去重</span></span><br><span class="line"><span class="keyword">select</span> job <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">DISTINCT</span> job <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="comment">-- 别名（字段，表）</span></span><br><span class="line"><span class="keyword">select</span> empno  员工编号,ename 员工姓名 <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="keyword">select</span> ename,sal,sal*<span class="number">1.05</span> 新工资 <span class="keyword">from</span> emp;</span><br><span class="line"></span><br><span class="line"><span class="keyword">select</span> ename,sal <span class="keyword">from</span> emp e ;</span><br><span class="line"><span class="keyword">select</span> e.ename,e.sal <span class="keyword">from</span> emp e ;</span><br><span class="line"><span class="comment">-- null 的判断</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> comm <span class="keyword">is</span> <span class="keyword">not</span> <span class="literal">null</span> ;</span><br><span class="line"></span><br><span class="line"><span class="comment">--模糊查询</span></span><br><span class="line"><span class="comment">--查询所有S打头的员工信息（模糊查询） % 代表0到多个字符</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> ename <span class="keyword">like</span> <span class="string">'S%'</span>;</span><br><span class="line"><span class="comment">--查询所有N结尾的</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> ename <span class="keyword">like</span> <span class="string">'%N'</span>;</span><br><span class="line"><span class="comment">--查询所有包含S的</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> ename <span class="keyword">like</span> <span class="string">'%S%'</span>;</span><br><span class="line"><span class="comment">--查询所有第二个字符为L的员工信息</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> ename <span class="keyword">like</span> <span class="string">'__L%'</span>;</span><br><span class="line"></span><br><span class="line"><span class="comment">--排序  (默认升序   order by字段 [asc]  | desc)</span></span><br><span class="line"><span class="comment">--默认  升序</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">order</span> <span class="keyword">by</span> sal ;</span><br><span class="line"><span class="comment">--降序</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">order</span> <span class="keyword">by</span> sal <span class="keyword">desc</span> ;</span><br><span class="line"><span class="comment">--按照工资的降序排序，如果工资一样的，则按照empno的升序排序(用逗号)</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">order</span> <span class="keyword">by</span> sal <span class="keyword">desc</span> , empno <span class="keyword">ASC</span>;</span><br><span class="line"><span class="comment">--限制结果查询（limit m,n)  m代表起始索引，n代表记录的数目,limit 仅适用于MySQL</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">limit</span> <span class="number">5</span>,<span class="number">5</span>;</span><br><span class="line"></span><br><span class="line"><span class="comment">--查询20号部门工资最高的员工的信息</span></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp <span class="keyword">where</span> deptno = <span class="number">20</span> <span class="keyword">order</span> <span class="keyword">by</span> sal <span class="keyword">desc</span> <span class="keyword">limit</span> <span class="number">0</span>,<span class="number">1</span> ;</span><br><span class="line"></span><br><span class="line"><span class="comment">--计算3的15次方</span></span><br><span class="line"></span><br><span class="line"><span class="comment">--数学函数</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">ABS</span>(<span class="number">10</span>);  <span class="comment">--绝对值</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">CEIL</span>(<span class="number">-12.3</span>);   <span class="comment">--向上取整</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">FLOOR</span>(<span class="number">12.5</span>);   <span class="comment">--向下取整</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">ROUND</span>(<span class="number">12.6</span>);   <span class="comment">--四舍五入</span></span><br><span class="line"><span class="keyword">select</span> ROUNT(<span class="number">12.49</span>，<span class="number">1</span>);   </span><br><span class="line"><span class="keyword">select</span> <span class="keyword">POW</span>(<span class="number">3</span>,<span class="number">3</span>);   <span class="comment">--幂运算</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">RAND</span>();     <span class="comment">--随机数[0,1)</span></span><br><span class="line"></span><br><span class="line"></span><br><span class="line"><span class="comment">--字符串函数</span></span><br><span class="line">desc emp ;</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">LENGTH</span>(ename) <span class="keyword">from</span> emp ;    <span class="comment">--获取字符串长度</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">length</span>(<span class="string">'this is a apple'</span>);</span><br><span class="line"></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">LOWER</span>(ename) <span class="keyword">from</span> emp ;  <span class="comment">--转换为小写</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">UPPER</span>(<span class="string">'this is a page'</span>);   <span class="comment">-- 转换大小写</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">substr</span>(<span class="string">'aabbcc'</span>,<span class="number">1</span>,<span class="number">2</span>);      <span class="comment">-- 从1开始</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">LPAD</span>(<span class="string">'smith'</span>,<span class="number">10</span>,<span class="string">'*'</span>);  <span class="comment">-- 开始字符串，总长度，padstr填充的字符</span></span><br><span class="line"><span class="keyword">select</span> RPAD(<span class="string">'smith'</span>,<span class="number">10</span>,<span class="string">'*'</span>);  <span class="comment">-- 右填充</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">TRIM</span>(<span class="string">'     smi  th'</span>);  <span class="comment">--去空格</span></span><br><span class="line"></span><br><span class="line"><span class="comment">-- 日期</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">NOW</span>();</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">sysdate</span>();</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">CURRENT_DATE</span>();     <span class="comment">--当前日期</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">current_time</span>();     <span class="comment">--当前时间</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">YEAR</span>(<span class="string">'1998-09-09'</span>);</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">MONTH</span>(<span class="string">'1998-09-09'</span>);</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">DAY</span>(<span class="string">'1998-09-09'</span>);</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">DATE_ADD</span>(<span class="string">'1998-09-09'</span>,<span class="built_in">INTERVAL</span> <span class="number">2</span> <span class="keyword">YEAR</span>);</span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> student ;</span><br><span class="line"><span class="keyword">alter</span> <span class="keyword">table</span> student <span class="keyword">add</span> birthday <span class="built_in">date</span> <span class="keyword">AFTER</span> age;</span><br><span class="line"></span><br><span class="line"><span class="comment">-- 聚合函数</span></span><br><span class="line"><span class="comment">--count /sum/avg/max/min</span></span><br><span class="line"></span><br><span class="line"><span class="comment">-- 员工数（统计记录数）</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">count</span>(*) <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">count</span>(<span class="number">1</span>) <span class="keyword">from</span> emp ;</span><br><span class="line"></span><br><span class="line"><span class="comment">-- 统计非空字段数目</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">count</span>(comm) <span class="keyword">from</span> emp;</span><br><span class="line"><span class="comment">-- SUM</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">sum</span>(sal) <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="comment">-- AVG </span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">avg</span>(sal) <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="comment">-- MIN</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">min</span>(sal) <span class="keyword">from</span> emp ;</span><br><span class="line"><span class="comment">-- MAX </span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">max</span>(sal) <span class="keyword">from</span> emp ;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line"><span class="comment">-- 分组函数 GROUP BY deptno</span></span><br><span class="line"><span class="comment">-- 每个部门的平均工资</span></span><br><span class="line"><span class="comment">-- group by 根据条件字段的值返回相应的记录数；但是在select字句中，只能出现聚合函数或者分组的条件字段。</span></span><br><span class="line"><span class="keyword">select</span> deptno, <span class="keyword">avg</span>(sal) <span class="keyword">from</span> emp <span class="keyword">GROUP</span> <span class="keyword">BY</span> deptno ;</span><br><span class="line"></span><br><span class="line"><span class="comment">-- 各个职位员工数？ job</span></span><br><span class="line"><span class="keyword">select</span> job, <span class="keyword">count</span>(*) <span class="keyword">from</span> emp <span class="keyword">group</span> <span class="keyword">by</span> job;</span><br><span class="line"><span class="comment">-- 平均工资大于2000的部门的部门编号和平均工资？   where 不能放group by之后，having可以，group by 和having  经常配套使用</span></span><br><span class="line">   <span class="comment">-- 1.求出每个部门的平均工资</span></span><br><span class="line">	 <span class="comment">-- 2.平均工资&gt;2000</span></span><br><span class="line"><span class="keyword">select</span> deptno,<span class="keyword">avg</span>(sal) <span class="keyword">from</span> emp <span class="keyword">GROUP</span> <span class="keyword">BY</span> deptno <span class="keyword">having</span> <span class="keyword">avg</span>(sal) &gt; <span class="number">2000</span>;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line"><span class="comment">-- where 和 having 的区别</span></span><br><span class="line"><span class="comment">-- 查询工资大于1500的每个部门的平均工资</span></span><br><span class="line"><span class="keyword">select</span> deptno, <span class="keyword">avg</span>(sal) <span class="keyword">from</span> emp <span class="keyword">where</span> sal &gt; <span class="number">1500</span> <span class="keyword">GROUP</span> <span class="keyword">BY</span> deptno ;</span><br><span class="line"><span class="comment">-- 查询平均工资大于1500的部门编号和平均工资</span></span><br><span class="line"><span class="keyword">select</span> deptno,<span class="keyword">avg</span>(sal) <span class="keyword">from</span> emp <span class="keyword">GROUP</span> <span class="keyword">BY</span> deptno <span class="keyword">having</span> <span class="keyword">avg</span>(sal) &gt; <span class="number">1500</span> ;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line"><span class="comment">-- 加密函数</span></span><br><span class="line"><span class="keyword">select</span> <span class="keyword">MD5</span>(<span class="string">'root'</span>);</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">SHA</span>(<span class="string">'root'</span>);</span><br><span class="line"><span class="keyword">select</span> <span class="keyword">PASSWORD</span>(<span class="string">'root'</span>);</span><br><span class="line"></span><br><span class="line"><span class="comment">-- 外键约束： foreign key</span></span><br><span class="line"><span class="keyword">create</span> <span class="keyword">table</span> classroom(</span><br><span class="line">	cid <span class="built_in">int</span> PRIMARY <span class="keyword">key</span>,</span><br><span class="line">	cname <span class="built_in">varchar</span>(<span class="number">20</span>)</span><br><span class="line">);</span><br><span class="line"><span class="keyword">alter</span> <span class="keyword">table</span> student <span class="keyword">add</span> <span class="keyword">CONSTRAINT</span> FK_CID FOREIGN <span class="keyword">KEY</span>(cid) <span class="keyword">REFERENCES</span> classroom(cid);</span><br><span class="line"></span><br><span class="line"><span class="keyword">select</span> * <span class="keyword">from</span> emp ;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line"><span class="comment">-- 高级查询</span></span><br><span class="line"><span class="comment">-- 多表查询</span></span><br><span class="line"><span class="comment">-- 查询的结果集分布于多张表</span></span><br><span class="line"><span class="comment">-- 查询员工编号为7788的员工姓名和部门名称。</span></span><br><span class="line"><span class="comment">-- 内连接 ，注意：1 内连接的结果集与连接顺序无关 2 在多张表中都出现的数据才会出现在内连接的结果集中</span></span><br><span class="line"><span class="keyword">select</span> e.ename,d.dname <span class="keyword">from</span> emp e ,dept d <span class="keyword">where</span> e.empno = <span class="number">7788</span> <span class="keyword">and</span> e.deptno = d.deptno;</span><br><span class="line"><span class="comment">-- inner join ...on....</span></span><br><span class="line"><span class="keyword">select</span> ename,dname <span class="keyword">from</span> emp <span class="keyword">inner</span> <span class="keyword">join</span> dept <span class="keyword">on</span> emp.deptno = dept.deptno ;</span><br><span class="line"><span class="comment">-- inner join ...using... (局限,当deptno不同时)</span></span><br><span class="line"><span class="keyword">select</span> ename,dname  <span class="keyword">from</span> emp <span class="keyword">inner</span> <span class="keyword">join</span> dept <span class="keyword">using</span>(deptno)</span><br></pre></td></tr></table></figure>

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      $(".local-search-pop-overlay").remove();
      $('body').css('overflow', '');
    }

    function proceedsearch() {
      $("body")
        .append('<div class="search-popup-overlay local-search-pop-overlay"></div>')
        .css('overflow', 'hidden');
      $('.search-popup-overlay').click(onPopupClose);
      $('.popup').toggle();
      var $localSearchInput = $('#local-search-input');
      $localSearchInput.attr("autocapitalize", "none");
      $localSearchInput.attr("autocorrect", "off");
      $localSearchInput.focus();
    }

    // search function;
    var searchFunc = function(path, search_id, content_id) {
      'use strict';

      // start loading animation
      $("body")
        .append('<div class="search-popup-overlay local-search-pop-overlay">' +
          '<div id="search-loading-icon">' +
          '<i class="fa fa-spinner fa-pulse fa-5x fa-fw"></i>' +
          '</div>' +
          '</div>')
        .css('overflow', 'hidden');
      $("#search-loading-icon").css('margin', '20% auto 0 auto').css('text-align', 'center');


      $.ajax({
        url: path,
        dataType: isXml ? "xml" : "json",
        async: true,
        success: function(res) {
          // get the contents from search data
          isfetched = true;
          $('.popup').detach().appendTo('.header-inner');
          var datas = isXml ? $("entry", res).map(function() {
            return {
              title: $("title", this).text(),
              content: $("content",this).text(),
              url: $("url" , this).text()
            };
          }).get() : res;
          var input = document.getElementById(search_id);
          var resultContent = document.getElementById(content_id);
          var inputEventFunction = function() {
            var searchText = input.value.trim().toLowerCase();
            var keywords = searchText.split(/[\s\-]+/);
            if (keywords.length > 1) {
              keywords.push(searchText);
            }
            var resultItems = [];
            if (searchText.length > 0) {
              // perform local searching
              datas.forEach(function(data) {
                var isMatch = false;
                var hitCount = 0;
                var searchTextCount = 0;
                var title = data.title.trim();
                var titleInLowerCase = title.toLowerCase();
                var content = data.content.trim().replace(/<[^>]+>/g,"");

                var contentInLowerCase = content.toLowerCase();
                var articleUrl = decodeURIComponent(data.url).replace(/\/{2,}/g, '/');
                var indexOfTitle = [];
                var indexOfContent = [];
                // only match articles with not empty titles
                if(title != '') {
                  keywords.forEach(function(keyword) {
                    function getIndexByWord(word, text, caseSensitive) {
                      var wordLen = word.length;
                      if (wordLen === 0) {
                        return [];
                      }
                      var startPosition = 0, position = [], index = [];
                      if (!caseSensitive) {
                        text = text.toLowerCase();
                        word = word.toLowerCase();
                      }
                      while ((position = text.indexOf(word, startPosition)) > -1) {
                        index.push({position: position, word: word});
                        startPosition = position + wordLen;
                      }
                      return index;
                    }

                    indexOfTitle = indexOfTitle.concat(getIndexByWord(keyword, titleInLowerCase, false));
                    indexOfContent = indexOfContent.concat(getIndexByWord(keyword, contentInLowerCase, false));
                  });
                  if (indexOfTitle.length > 0 || indexOfContent.length > 0) {
                    isMatch = true;
                    hitCount = indexOfTitle.length + indexOfContent.length;
                  }
                }

                // show search results

                if (isMatch) {
                  // sort index by position of keyword

                  [indexOfTitle, indexOfContent].forEach(function (index) {
                    index.sort(function (itemLeft, itemRight) {
                      if (itemRight.position !== itemLeft.position) {
                        return itemRight.position - itemLeft.position;
                      } else {
                        return itemLeft.word.length - itemRight.word.length;
                      }
                    });
                  });

                  // merge hits into slices

                  function mergeIntoSlice(text, start, end, index) {
                    var item = index[index.length - 1];
                    var position = item.position;
                    var word = item.word;
                    var hits = [];
                    var searchTextCountInSlice = 0;
                    while (position + word.length <= end && index.length != 0) {
                      if (word === searchText) {
                        searchTextCountInSlice++;
                      }
                      hits.push({position: position, length: word.length});
                      var wordEnd = position + word.length;

                      // move to next position of hit

                      index.pop();
                      while (index.length != 0) {
                        item = index[index.length - 1];
                        position = item.position;
                        word = item.word;
                        if (wordEnd > position) {
                          index.pop();
                        } else {
                          break;
                        }
                      }
                    }
                    searchTextCount += searchTextCountInSlice;
                    return {
                      hits: hits,
                      start: start,
                      end: end,
                      searchTextCount: searchTextCountInSlice
                    };
                  }

                  var slicesOfTitle = [];
                  if (indexOfTitle.length != 0) {
                    slicesOfTitle.push(mergeIntoSlice(title, 0, title.length, indexOfTitle));
                  }

                  var slicesOfContent = [];
                  while (indexOfContent.length != 0) {
                    var item = indexOfContent[indexOfContent.length - 1];
                    var position = item.position;
                    var word = item.word;
                    // cut out 100 characters
                    var start = position - 20;
                    var end = position + 80;
                    if(start < 0){
                      start = 0;
                    }
                    if (end < position + word.length) {
                      end = position + word.length;
                    }
                    if(end > content.length){
                      end = content.length;
                    }
                    slicesOfContent.push(mergeIntoSlice(content, start, end, indexOfContent));
                  }

                  // sort slices in content by search text's count and hits' count

                  slicesOfContent.sort(function (sliceLeft, sliceRight) {
                    if (sliceLeft.searchTextCount !== sliceRight.searchTextCount) {
                      return sliceRight.searchTextCount - sliceLeft.searchTextCount;
                    } else if (sliceLeft.hits.length !== sliceRight.hits.length) {
                      return sliceRight.hits.length - sliceLeft.hits.length;
                    } else {
                      return sliceLeft.start - sliceRight.start;
                    }
                  });

                  // select top N slices in content

                  var upperBound = parseInt('1');
                  if (upperBound >= 0) {
                    slicesOfContent = slicesOfContent.slice(0, upperBound);
                  }

                  // highlight title and content

                  function highlightKeyword(text, slice) {
                    var result = '';
                    var prevEnd = slice.start;
                    slice.hits.forEach(function (hit) {
                      result += text.substring(prevEnd, hit.position);
                      var end = hit.position + hit.length;
                      result += '<b class="search-keyword">' + text.substring(hit.position, end) + '</b>';
                      prevEnd = end;
                    });
                    result += text.substring(prevEnd, slice.end);
                    return result;
                  }

                  var resultItem = '';

                  if (slicesOfTitle.length != 0) {
                    resultItem += "<li><a href='" + articleUrl + "' class='search-result-title'>" + highlightKeyword(title, slicesOfTitle[0]) + "</a>";
                  } else {
                    resultItem += "<li><a href='" + articleUrl + "' class='search-result-title'>" + title + "</a>";
                  }

                  slicesOfContent.forEach(function (slice) {
                    resultItem += "<a href='" + articleUrl + "'>" +
                      "<p class=\"search-result\">" + highlightKeyword(content, slice) +
                      "...</p>" + "</a>";
                  });

                  resultItem += "</li>";
                  resultItems.push({
                    item: resultItem,
                    searchTextCount: searchTextCount,
                    hitCount: hitCount,
                    id: resultItems.length
                  });
                }
              })
            };
            if (keywords.length === 1 && keywords[0] === "") {
              resultContent.innerHTML = '<div id="no-result"><i class="fa fa-search fa-5x"></i></div>'
            } else if (resultItems.length === 0) {
              resultContent.innerHTML = '<div id="no-result"><i class="fa fa-frown-o fa-5x"></i></div>'
            } else {
              resultItems.sort(function (resultLeft, resultRight) {
                if (resultLeft.searchTextCount !== resultRight.searchTextCount) {
                  return resultRight.searchTextCount - resultLeft.searchTextCount;
                } else if (resultLeft.hitCount !== resultRight.hitCount) {
                  return resultRight.hitCount - resultLeft.hitCount;
                } else {
                  return resultRight.id - resultLeft.id;
                }
              });
              var searchResultList = '<ul class=\"search-result-list\">';
              resultItems.forEach(function (result) {
                searchResultList += result.item;
              })
              searchResultList += "</ul>";
              resultContent.innerHTML = searchResultList;
            }
          }

          if ('auto' === 'auto') {
            input.addEventListener('input', inputEventFunction);
          } else {
            $('.search-icon').click(inputEventFunction);
            input.addEventListener('keypress', function (event) {
              if (event.keyCode === 13) {
                inputEventFunction();
              }
            });
          }

          // remove loading animation
          $(".local-search-pop-overlay").remove();
          $('body').css('overflow', '');

          proceedsearch();
        }
      });
    }

    // handle and trigger popup window;
    $('.popup-trigger').click(function(e) {
      e.stopPropagation();
      if (isfetched === false) {
        searchFunc(path, 'local-search-input', 'local-search-result');
      } else {
        proceedsearch();
      };
    });

    $('.popup-btn-close').click(onPopupClose);
    $('.popup').click(function(e){
      e.stopPropagation();
    });
    $(document).on('keyup', function (event) {
      var shouldDismissSearchPopup = event.which === 27 &&
        $('.search-popup').is(':visible');
      if (shouldDismissSearchPopup) {
        onPopupClose();
      }
    });
  </script>


  <script src="https://www.gstatic.com/firebasejs/4.6.0/firebase.js"></script>
  <script src="https://www.gstatic.com/firebasejs/4.6.0/firebase-firestore.js"></script>

    <script src="https://cdnjs.cloudflare.com/ajax/libs/bluebird/3.5.1/bluebird.core.min.js"></script>

  <script>
    (function () {

      firebase.initializeApp({
        apiKey: '',
        projectId: ''
      })

      function getCount(doc, increaseCount) {
        //increaseCount will be false when not in article page

        return doc.get().then(function (d) {
          var count
          if (!d.exists) { //has no data, initialize count
            if (increaseCount) {
              doc.set({
                count: 1
              })
              count = 1
            }
            else {
              count = 0
            }
          }
          else { //has data
            count = d.data().count
            if (increaseCount) {
              if (!(window.localStorage && window.localStorage.getItem(title))) { //if first view this article
                doc.set({ //increase count
                  count: count + 1
                })
                count++
              }
            }
          }
          if (window.localStorage && increaseCount) { //mark as visited
            localStorage.setItem(title, true)
          }

          return count
        })
      }

      function appendCountTo(el) {
        return function (count) {
          $(el).append(
            $('<span>').addClass('post-visitors-count').append(
              $('<span>').addClass('post-meta-divider').text('|')
            ).append(
              $('<span>').addClass('post-meta-item-icon').append(
                $('<i>').addClass('fa fa-users')
              )
              ).append($('<span>').text('阅读次数 ' + count))
          )
        }
      }

      var db = firebase.firestore()
      var articles = db.collection('articles')

      //https://hexo.io/docs/variables.html
      var isPost = '常见SQL语句'.length > 0
      var isArchive = '' === 'true'
      var isCategory = ''.length > 0
      var isTag = ''.length > 0

      if (isPost) { //is article page
        var title = '常见SQL语句'
        var doc = articles.doc(title)

        getCount(doc, true).then(appendCountTo($('.post-meta')))
      }
      else if (!isArchive && !isCategory && !isTag) { //is index page
        var titles = [] //array to titles

        var postsstr = '' //if you have a better way to get titles of posts, please change it
        eval(postsstr)

        var promises = titles.map(function (title) {
          return articles.doc(title)
        }).map(function (doc) {
          return getCount(doc)
        })
        Promise.all(promises).then(function (counts) {
          var metas = $('.post-meta')
          counts.forEach(function (val, idx) {
            appendCountTo(metas[idx])(val)
          })
        })
      }
    })()
  </script>


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