How to write function for optional parameters in postgresql?
<p>My requirement is write optional parameters to a function.Parameters are optional sometimes i will add or i will not pass parameters to function.Can anyone help me how to write function.</p>

<p>I am writing like </p>

<pre><code>select * 
from test 
where field3 in ('value1','value2') 
 and ($1 is null or field1 = $1) 
 and ($2 is null or field2 = $2) 
 and ($3 is null or field3 = $3);
</code></pre>

<p>i am passing parameters to Query,But my output is not expected.when i pass all three parameters my output is correct,otherwise it is not expected output.</p>