Re: Mysql too Slow when Copying to Tmp Table

[karen wang]

thanks for you help
I excuted “flush tables" before i excute this query everytime.
when i excute the query a second time without 'flush tables' command,it's so fast.

A bigger "optimization" comes from noticing that the two tables have exactly the same number of rows. Are they 1:1?
yes it's 1:1 but we cant put the data in a single table because another reason.

I changed some column's character attribute as you suggested.
it's last 0.36seconds when i run this query in SecureCRT Client.
it's last 11.8419seconds when i run this query in phpmyadmin Client.
it's last 4.031seconds when i run this query in Navicat Client.
（I try some times!）
what is this caused??