如果查询的结果少，可以把查询结果当子集，再查另一张表，比join的速度快得多得多

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
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select up.UP_NAME as printName,count(1) as qty from riv_print_history_l phl  JOIN tab_user_profile up

 on up.UP_USER_ID = phl.PHL_PRINT_USER_ID

 where

 phl.CREATE_TIME >= '2017-00-15 00:00:00' and phl.CREATE_TIME < '2017-09-21 00:00:00'

GROUP BY  phl.PHL_PRINT_USER_ID;

select

(select UP_NAME from tab_user_profile where UP_USER_ID = tab1.PHL_PRINT_USER_ID)

     as printName,tab1.qty from

(select PHL_PRINT_USER_ID,count(1) as qty from riv_print_history_l

 where CREATE_TIME >= '2017-00-15 00:00:00' and CREATE_TIME < '2017-09-21 01:00:00' GROUP BY  PHL_PRINT_USER_ID)tab1;

tab_user_profile 116行

riv_print_history_l 640746行

select PHL_PRINT_USER_ID,count(1) as qty from riv_print_history_l

 where CREATE_TIME >= '2017-00-15 00:00:00' and CREATE_TIME < '2017-09-21 01:00:00' GROUP BY  PHL_PRINT_USER_ID
查出的结果只有3行

第一个用时10s，第二个用时0.6s