Question

我需要从多个表（通过ID列相关）收集计数，所有这些都在一个查询中，我可以参数化以便在其他地方的某些动态SQL中使用。这就是我到目前为止所做的：

SELECT  revenue.count(*),
        constituent.count(*) 
FROM REVENUE
INNER JOIN CONSTITUENT 
    ON REVENUE.CONSTITUENTID = CONSTITUENT.ID

这不起作用，因为它不知道如何处理计数，但我不确定使用正确的语法。

为了澄清一点，我不希望每个ID有一条记录，而是每个表的总计数，我只需将它们合并为一个脚本。

Answer 1

这样可行：

select MAX(case when SourceTable = 'Revenue' then total else 0 end) as RevenueCount,
       MAX(case when SourceTable = 'Constituent' then total else 0 end) as ConstituentCount
from (
    select count(*) as total, 'Revenue' as SourceTable
    FROM revenue
    union
    select count(*), 'Constituent'
    from Constituent
) x

Answer 2

也许你需要结合......

select * from (
SELECT 'revenue' tbl, count(*), constituentid id FROM REVENUE
union
SELECT 'constituent', count(*), id  FROM CONSTITUENT
)
where id = ?

Answer 3

您想要每个ID一条记录吗？

SELECT coalesce(c.id, r.ConstituentID) "ID", COUNT(r.ConstituentID) "Revenue", COUNT(c.ID) "Constituent"
FROM Revenue r
FULL JOIN constituent c on c.id = r.ConstituentId
GROUP BY coalesce(c.id, r.ConstituentID)

或者您想要给定ID的计数吗？

SELECT c.ID "ID", COUNT(r.ConstituentID) "Revenue", COUNT(c.ID) "Constituent"
FROM Revenue r
INNER JOIN constituent c on c.id = r.ConstituentId
WHERE c.ID = @ID
GROUP BY c.id

或者你想要两个表中的总计数？

SELECT 'Revenue' "Table", COUNT(*) "Rows" FROM Revenue
UNION
SELECT 'Constituents', COUNT(*) FROM Constituents

请注意，在最后，表格相关的事实是无关紧要的。

Answer 4

你说你想用动态sql做这件事。这是你在找什么？

DECLARE @sql nvarchar(4000)

SELECT @sql = COALESCE(@sql + N' UNION ALL '+CHAR(13),'') + N'SELECT '''+QUOTENAME(table_name)+''',COUNT(*) FROM '+QUOTENAME(table_name)
FROM (VALUES('t1'),('t2'),('t3')) table_list(table_name)

PRINT @sql

在单个查询中收集多个表的计数

4 个答案: