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