SQL Select 语句的组合

Question

我正在尝试拍摄数据库中某些表的状态的“快照”。我已经完成了其中的一些，目前正在处理最后一个，但是对于最后一个，我需要查询两个不同的表。

到目前为止已经尝试过以下方法：

SELECT
     COUNT(Name) as CRIT,
     branch
FROM(
SELECT
    A.Name,
    A.branch,
    B.score,
    B.last_found
FROM
    TableA as A
INNER JOIN TableB as B ON A.Name= V.Name
WHERE
    B.state <> 'DONE'
AND DATEDIFF(day, B.last_found, GETDATE()) > 30
AND CAST(B.score as float) > 8) AS X
GROUP BY
    branch

这将返回我所需要的一部分： ()

我可以稍微修改一下代码：

SELECT
     COUNT(Name) as LOW,
     branch
FROM(
SELECT
    A.Name,
    A.branch,
    B.score,
    B.last_found
FROM
    TableA as A
INNER JOIN TableB as B ON A.Name= V.Name
WHERE
    B.state <> 'DONE'
AND DATEDIFF(day, B.last_found, GETDATE()) > 30
AND CAST(B.score as float) < 4) AS X
GROUP BY
    branch

得到以下内容： ()

这又是我需要的另一部分。最终输出应该是上述两个查询的组合，并且应该有 3 列：

CRIT 低分支

如果我不清楚，请原谅并感谢您的帮助！！

Answer 1

您想要条件聚合：

SELECT
   a.branch,
   COUNT(CASE WHEN CAST(b.score as float) > 8 THEN 1 END) AS crit,
   COUNT(CASE WHEN CAST(b.score as float) < 4 THEN 1 END) AS low
FROM tablea AS a
INNER JOIN tableb AS b ON b.name = a.name
WHERE b.state <> 'DONE'
AND DATEDIFF(day, b.last_found, GETDATE()) > 30
GROUP BY a.branch;