title: select apostrophes from Postgresql
body: <p>I have a row cell value with two apostrophes in postgresql version 9.1 as follows:</p>
  
  <pre><code>col1  col2
  ''    1
  ''    2
  aa    3
  aa    4
  </code></pre>
  
  <p>Now i want to select those rows with '' from col1</p>
  
  <p>I tried:</p>
  
  <pre><code>select * from table1 where col1 like '''''%'
  </code></pre>
  
  <p>but return nothing.</p>
  
  <pre><code>select * from table1 where col1 = ''''''
  </code></pre>
  
  <p>but return nothing.</p>
  
  <pre><code>select * from table1 where col1 = $$''''$$
  </code></pre>
  
  <p>but also return nothing.</p>
  
  <pre><code>select * from table1 where col1 like $$''%$$
  </code></pre>
  
  <p>but also return nothing.</p>
  
  <p>would anyone can help?
  thx</p>