[英]SQL - merge two queries with different number of columns in select statement into one
[英]Merge of two select queries
我想將這兩個Select查詢合並到單個查詢中。 我怎樣才能做到這一點?
SELECT link_id, COUNT(*) FROM Loc GROUP BY link_id
SELECT Slink.[xlink:Show],Loc.[xlink:show],
Slink.[xlink:actuate],Loc.[xlink:actuate] ,
href, Sem.SemRoleDescrip
FROM Sem JOIN Loc ON
Sem.SemRoleId = Loc.SemRoleId
JOIN Slink ON Slink.link_id = Loc.link_id
COUNT
語句添加為子查詢 (LEFT) JOIN
使用SLink
表(LEFT) JOIN
此子選擇 LinkCount
添加到所選值的列表。 SELECT Slink.[xlink:Show]
, Loc.[xlink:show]
, Slink.[xlink:actuate]
, Loc.[xlink:actuate]
, href
, Sem.SemRoleDescrip
, SLinkCount.LinkCount
FROM Sem
JOIN Loc ON Sem.SemRoleId = Loc.SemRoleId
JOIN Slink ON Slink.link_id = Loc.link_id
LEFT JOIN (
SELECT link_id, COUNT(*) AS LinkCount
FROM Loc
GROUP BY
link_id
) SLinkCount ON SLinkCount.link_id = Slink.link_id
您可能需要閱讀參考手冊中的“子查詢”
12.2.9.8。 FROM子句中的子查詢
子查詢在
SELECT
語句的FROM
子句中是合法的。 實際語法是:
SELECT ... FROM (subquery) [AS] name ...
[AS]
name子句是強制性的,因為FROM
子句中的每個表都必須有一個名稱。 子查詢選擇列表中的任何列都必須具有唯一的名稱。
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