1920.154s 0.309s 30817

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