MyISAM HASH  restart-buffer

 CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 1627;
UPDATE wtmp SET grab_year=1628;
UPDATE grab_sales_rank_month wt LEFT JOIN wtmp ON wtmp.autoid=wt.autoid SET wt.grab_year=1629;
SELECT * FROM grab_sales_rank_month; [SQL]CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 1627;
受影响的行: 0
时间: 0.002s [SQL]
UPDATE wtmp SET grab_year=1628;
受影响的行: 0
时间: 0.000s [SQL]
UPDATE grab_sales_rank_month wt LEFT JOIN wtmp ON wtmp.autoid=wt.autoid SET wt.grab_year=1629;
受影响的行: 30817
时间: 0.309s [SQL]
SELECT * FROM grab_sales_rank_month;
受影响的行: 0
时间: 0.021s
 CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 2016;
UPDATE wtmp SET grab_year=1616;
UPDATE grab_sales_rank_month wt SET grab_year=(SELECT grab_year FROM wtmp WHERE autoid=wt.autoid);
SELECT * FROM grab_sales_rank_month; [SQL]CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 2016;
受影响的行: 25953
时间: 0.090s [SQL]
UPDATE wtmp SET grab_year=1616;
受影响的行: 25953
时间: 0.147s [SQL]
UPDATE grab_sales_rank_month wt SET grab_year=(SELECT grab_year FROM wtmp WHERE autoid=wt.autoid);
受影响的行: 30817
时间: 1920.154s [SQL]
SELECT * FROM grab_sales_rank_month;
受影响的行: 0
时间: 0.023s
05-08 08:22