1920.154s 0.309s 30817

MyISAM HASH  restart-buffer

 1 CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 1627;
 2 UPDATE wtmp SET grab_year=1628;
 3 UPDATE grab_sales_rank_month wt LEFT JOIN wtmp ON wtmp.autoid=wt.autoid SET wt.grab_year=1629;
 4 SELECT * FROM grab_sales_rank_month; 
 5 
 6 [SQL]CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 1627;
 7 受影响的行: 0
 8 时间: 0.002s
 9 
10 [SQL]
11 UPDATE wtmp SET grab_year=1628;
12 受影响的行: 0
13 时间: 0.000s
14 
15 [SQL]
16 UPDATE grab_sales_rank_month wt LEFT JOIN wtmp ON wtmp.autoid=wt.autoid SET wt.grab_year=1629;
17 受影响的行: 30817
18 时间: 0.309s
19 
20 [SQL]
21 SELECT * FROM grab_sales_rank_month;
22 受影响的行: 0
23 时间: 0.021s
 1 CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 2016;
 2 UPDATE wtmp SET grab_year=1616;
 3 UPDATE grab_sales_rank_month wt SET grab_year=(SELECT grab_year FROM wtmp  WHERE autoid=wt.autoid);
 4 SELECT * FROM grab_sales_rank_month;
 5 
 6 [SQL]CREATE TEMPORARY TABLE wtmp AS SELECT * FROM grab_sales_rank_month WHERE grab_year = 2016;
 7 受影响的行: 25953
 8 时间: 0.090s
 9 
10 [SQL]
11 UPDATE wtmp SET grab_year=1616;
12 受影响的行: 25953
13 时间: 0.147s
14 
15 [SQL]
16 UPDATE grab_sales_rank_month wt SET grab_year=(SELECT grab_year FROM wtmp  WHERE autoid=wt.autoid);
17 受影响的行: 30817
18 时间: 1920.154s
19 
20 [SQL]
21 SELECT * FROM grab_sales_rank_month;
22 受影响的行: 0
23 时间: 0.023s
原文地址:https://www.cnblogs.com/rsapaper/p/6235844.html