Re: Null bind variable in where clause

From: Dave Cramer <pg(at)fastcrypt(dot)com>
To: Chris Stuhr <cstuhr(at)ephibian(dot)com>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Null bind variable in where clause
Date: 2007-05-01 11:21:39
Message-ID: 4906DD3E-322A-4E26-8600-B967AFA8A58F@fastcrypt.com
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This is a server issue.

If you really want this behaviour then

set
transform_null_equals = off to on

in postgresql.conf

Dave
On 30-Apr-07, at 9:34 PM, Chris Stuhr wrote:

> It looks like you can not use a bind variable when trying to match
> null in a where clause. Is there any way to get the desired effect
> without having to remove the bind variable and rewrite the query to
> "WHERE b IS null"?
>
> import java.sql.*;
>
> public class a {
>
> public static void main(String args[]) throws Exception {
> String sql = "CREATE TABLE t(a int, b int)";
> Class.forName("org.postgresql.Driver");
> Connection conn = DriverManager.getConnection(
> "jdbc:postgresql://10.20.1.70:5432/firm", "gaiam", "");
> try {
> Statement stmt = conn.createStatement();
> stmt.executeUpdate(sql);
> sql = "INSERT INTO t(a,b) VALUES (3,null)";
> stmt.executeUpdate(sql);
> stmt.close();
> } catch (SQLException sqle) {
> sqle.printStackTrace();
> }
>
> sql = "UPDATE t SET a = ? WHERE b = ?";
> PreparedStatement pstmt = conn.prepareStatement(sql);
> pstmt.setInt(1, 4);
> pstmt.setObject(2, null);
> int x = pstmt.executeUpdate();
> System.out.println(x);
> pstmt.close();
> Statement stmt = conn.createStatement();
> stmt.executeUpdate("DROP TABLE t");
> stmt.close();
> conn.close();
> }
> }
>
> Will print 0 instead of 1
>
> -Chris
>
>
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