On 04/05/2010 02:06 PM, chen jia wrote:
Hi there,
I run simple statement like this:
create table c
select * from a
union
select * from b;
where table a has 90,402,534 rows, and table b has 33,358,725 rows.
Both tables have the same three variables.
It's taken a long time, more
Union does a distinct on all results. UNION ALL will avoid that.
Regards,
Gavin Towey
-Original Message-
From: chen.1...@gmail.com [mailto:chen.1...@gmail.com] On Behalf Of chen jia
Sent: Monday, April 05, 2010 11:07 AM
To: mysql@lists.mysql.com
Subject: Slow Union Statement
Hi there,
Yes, that's the trick. Thank Rudy and Gavin.
Best,
Jia
On Mon, Apr 5, 2010 at 2:13 PM, Gavin Towey gto...@ffn.com wrote:
Union does a distinct on all results. UNION ALL will avoid that.
Regards,
Gavin Towey
-Original Message-
From: chen.1...@gmail.com [mailto:chen.1...@gmail.com]
