Question

我试图通过加入多个表来删除行，如你所见，但它会引发一个错误：

DELETE FROM Reg INNER JOIN
            RegDoc ON Reg.RegId = RegDoc.RegId INNER JOIN
            Doc ON RegDoc.DocId = Doc.DocId
WHERE Doc.Name LIKE N'%Title%'

收到错误：

第15行，第1行，第1行，第1行关键字“INNER”附近的语法不正确。

Answer 1

正确的语法是

DELETE [ FROM ] { <object> } 
[ FROM <table_source>]
[ WHERE { <search_condition> } ]

应用于您的示例，这将成为

DELETE FROM Reg 
FROM  Reg
      INNER JOIN RegDoc ON Reg.RegId = RegDoc.RegId 
      INNER JOIN Doc ON RegDoc.DocId = Doc.DocId
WHERE Doc.Name LIKE N'%Title%'

请注意两个对Reg表

的引用

这可以通过别名进一步缩短（虽然在这种情况下几乎不需要）

DELETE FROM r
FROM  Reg r
      INNER JOIN RegDoc ON r.RegId = RegDoc.RegId 
      INNER JOIN Doc ON RegDoc.DocId = Doc.DocId
WHERE Doc.Name LIKE N'%Title%'

MSDN示例

DELETE FROM Sales.SalesPersonQuotaHistory 
FROM Sales.SalesPersonQuotaHistory AS spqh
INNER JOIN Sales.SalesPerson AS sp
ON spqh.BusinessEntityID = sp.BusinessEntityID
WHERE sp.SalesYTD > 2500000.00;

Answer 2

使用此

DELETE 
FROM Reg 
FROM Reg 
INNER JOIN
            RegDoc ON Reg.RegId = RegDoc.RegId INNER JOIN
            Doc ON RegDoc.DocId = Doc.DocId
WHERE Doc.Name LIKE N'%Title%'

或者更清楚，恕我直言：

DELETE Reg 
FROM Reg 
INNER JOIN RegDoc 
  ON Reg.RegId = RegDoc.RegId 
INNER JOIN Doc 
  ON RegDoc.DocId = Doc.DocId
WHERE Doc.Name LIKE N'%Title%'

Answer 3

你可以这样做：

DELETE Reg
FROM Reg 
INNER JOIN RegDoc ON Reg.RegId = RegDoc.RegId 
INNER JOIN Doc ON RegDoc.DocId = Doc.DocId
WHERE Doc.Name LIKE N'%Title%'

Answer 4

您可以使用别名，但如果使用与表名不同的别名则更清楚：

DELETE  r 
FROM    Reg as r
INNER JOIN RegDoc rd ON r.RegId = rd.RegId 
INNER JOIN Doc d ON rd.DocId = d.DocId

您实际上也可以delete rd和delete d。

Answer 5

与其他答案（这些都很好）有点不同的方法

DELETE FROM Reg
WHERE Reg.RegID IN (SELECT RegDoc.RegId
                    FROM RegDoc
                      INNER JOIN Doc 
                        ON RegDoc.DocId = Doc.DocId
                    WHERE Doc.Name LIKE N'%Title%')

通过多个连接删除行

5 个答案: