如何传递空值以在plsql中进行选择

Question

I am trying to select some values in my table but when Invoicedate is null I got exception please help me!

my code :

query="select vend_name,vend_no from account where inv_date = '"+Invoicedate+"' or vend_no = "+Vendorno+" LIMIT 500";

please give any possible answer to me.

Answer 1

That's because in your code it will become inv_date = 'null' not inv_date is null .

You need to do inv_date "+(Invoiceddate==null?"is null":"= '"+Invoiceddate+"'")+" or

In general this is a bad way to do things though as you are open to SQL injection attacks and all sorts of other similar problems.

Use a PreparedStatement and all this will be handled for you:

PreparedStatement query = connection.prepareStatement("select vend_name,vend_no from account where inv_date = ? or vend_no = ? LIMIT ?");
query.setDate(1, Invoicedate);
... etc

Note also that you should follow the Java style conventions in variable naming etc, it will help people work with your code.