Question

表test列compname version和表Bugs列bugid compname

test的数据：

A 1.2
B 1.5
C 1.6
B 1.3
C 1.5
A 1.6
B 1.6

Bugs的数据：

1 A
1 C
2 A
2 B
3 A
3 B
3 C

查询是：

Output the compname where version=1.6 and affected by bugid=1 along with the first(min) version in which the component appeared

输出：
A 1.2
C 1.5

我正在使用此查询，但可以加快速度：

select compname,min(version) from test where compname IN (select compname from test where version='1.6' and compname IN (select compname from Bugs where bugid=1)) group by compname

Answer 1

联接速度更快，您需要额外的自我加入才能获得最低版本。

SELECT t.compname, min(t2.version)
FROM test t
INNER JOIN Bugs b
  ON t.compname = b.compname
INNER JOIN test t2
  ON t.compname = t2.compname
WHERE bugid = 1 AND t.version='1.6'
GROUP BY t.compname

（在我的测试中，它给出了你列出的相同结果）

Answer 2

您可以使用INNER JOIN：

SELECT test.compname, min(test.version) 
FROM test INNER JOIN Bugs
ON test.compname = Bugs.compname
WHERE test.version = '1.6' AND Bugs.bugid =1
GROUP BY test.compname

SQL查询以下输出？

2 个答案: