Question

我有3个数据库。

DB1 - I need to count the rows in Table2.column1 by RefNum from DB3
DB2 - Use the count from DB1 to update List table, QtyAdd column
DB3 - contains a RefNum that both DB1 and DB2 use.

以下查询将从DB1执行计数并更新DB2中的QtyAdd列。我无法弄清楚如何使用DB3中的RefNum添加到SELECT语句和UPDATE部分。

UPDATE List
SET QtyAdd = i.QTY
FROM (Select COUNT (Column1) AS QTY FROM DB2.dbo.Table2 WHERE (Column1 LIKE 'A%') and (RefNum = '2833')) i
WHERE (RefNum = '2833')

//Works but the RefNum is manually put in
//I have tried the following with no luck:

UPDATE List
SET QtyAdd = i.QTY
FROM (Select COUNT (Column1) AS QTY FROM DB2.dbo.Table2 WHERE (Column1 LIKE 'A%') and (RefNum = DB3.dbo.Ref.Refnum)) i
WHERE (RefNum = DB3.dbo.Ref.Refnum')

有什么建议吗？

Answer 1

您需要在子查询中使用GROUP BY，然后相应地JOIN使用其他表格。像这样：

UPDATE L
SET QtyAdd = i.QTY
FROM List L JOIN 
    (SELECT RefNum, COUNT(Column1) AS QTY 
     FROM DB2.dbo.Table2 
     WHERE Column1 LIKE 'A%'
     GROUP BY RefNum) i ON L.RefNum = i.RefNum JOIN 
    DB3.dbo.Ref r ON l.RefNum = r.RefNum

Condensed Fiddle Demo

SQL - 计数记录并将结果插入另一个表

1 个答案: