JOIN a table with a subquery

统计数据产品消耗量与产量

注意join 方向  

join中子查询

How to use subquery in JOIN operation in MySQL http://www.geeksengine.com/database/subquery/subquery-in-join-operation.php

SELECT * FROM (
SELECT COUNT(DISTINCT(tab_p_id)) AS num_used,uid FROM tab_used GROUP BY uid
) AS u LEFT JOIN (
SELECT COUNT(1) AS num_produced,uid FROM tab_produced WHERE status=0 GROUP BY uid )
AS p ON u.uid=p.uid

num_used uid num_produced uid1
7 34000818 7 34000818
5 34021448 5 34021448
4 34032175 4 34032175
2 34053736
1 34056643 1 34056643
3 34058625 1 34058625
1 34058871 6 34058871
1 34061376 2 34061376
2 34061642 2 34061642
2 34061911 2 34061911
1 34062103 21 34062103
1 34062125 23 34062125
5 50001361 5 50001361
1 50001496 3 50001496
1 50001902
3 50001937 3 50001937
2 50003549 4 50003549
3 50003739
1 50003912 5 50003912
3 50004712 3 50004712
6 50005136 3 50005136
1 50006475 1 50006475
1 50007058 1 50007058
2 50007241 10 50007241
1 50007396 13 50007396
2 50007436 5 50007436
2 50007453 4 50007453
3 50007469 2 50007469
11 50007565 11 50007565
1 50008000 10 50008000
3 50008751
8 50008905 8 50008905
1 50008952 10 50008952
9 50010160 10 50010160
4 50010671 5 50010671
1 50010844 7 50010844

SELECT p.uid FROM (
SELECT COUNT(DISTINCT(myproduct_id)) AS num_used,uid FROM myproduct_publish GROUP BY uid
) AS v
LEFT JOIN (
SELECT COUNT(1) AS num_produced,uid FROM myproduct WHERE status=0 GROUP BY uid
)
AS p ON v.uid=p.uid WHERE num_used>=num_produced