Update a table using JOIN in SQL Server?
我想更新表中的一列,在其他表上进行联接,例如:
1 2 3 4 5 6 | UPDATE table1 a INNER JOIN table2 b ON a.commonfield = b.[common field] SET a.CalculatedColumn= b.[Calculated Column] WHERE b.[common field]= a.commonfield AND a.BatchNO = '110' |
但它在抱怨:
Msg 170, Level 15, State 1, Line 2
Line 2: Incorrect syntax near 'a'.
这里怎么了?
您不太了解SQL Server的专有
1 2 3 4 5 6 | UPDATE t1 SET t1.CalculatedColumn = t2.[Calculated Column] FROM dbo.Table1 AS t1 INNER JOIN dbo.Table2 AS t2 ON t1.CommonField = t2.[Common Field] WHERE t1.BatchNo = '110'; |
如果您在做一些非常愚蠢的事情,例如不断尝试将一列的值设置为另一列的聚合(这违反了避免存储冗余数据的原则),则可以使用CTE(公共表表达式)-有关详细信息,请参阅此处和此处:
1 2 3 4 5 6 7 8 9 10 11 | ;WITH t2 AS ( SELECT [key], CalculatedColumn = SUM(some_column) FROM dbo.table2 GROUP BY [key] ) UPDATE t1 SET t1.CalculatedColumn = t2.CalculatedColumn FROM dbo.table1 AS t1 INNER JOIN t2 ON t1.[key] = t2.[key]; |
这真是愚蠢的原因,因为每次在
尝试如下:
1 2 3 4 5 6 | begin tran UPDATE a SET a.CalculatedColumn= b.[Calculated Column] FROM table1 a INNER JOIN table2 b ON a.commonfield = b.[common field] WHERE a.BatchNO = '110' commit tran |
亚伦以上的回答是完全的。
1 2 3 4 5 6 | UPDATE a SET a.CalculatedColumn = b.[Calculated Column] FROM Table1 AS a INNER JOIN Table2 AS b ON a.CommonField = b.[Common Field] WHERE a.BatchNo = '110'; |
只想添加当我们在更新表时尝试使用表的别名时SQL Server中出现此问题的原因,下面提到的语法将始终给出错误:
1 2 3 | update tableName t set t.name = 'books new' where t.id = 1 |
如果正在更新单个表或在使用join时进行更新,那么case可以是any。
尽管上面的查询在pl/sql中可以正常工作,但在SQL Server中却不行。
在SQL Server中使用表别名时更新表的正确方法是:
1 2 3 4 | update t set t.name = 'books new' from tableName t where t.id = 1 |
希望它能帮助大家理解为什么错误会出现在这里。
1 2 3 4 5 6 7 | MERGE table1 T USING table2 S ON T.CommonField = S."Common Field" AND T.BatchNo = '110' WHEN MATCHED THEN UPDATE SET CalculatedColumn = S."Calculated Column"; |
1 2 3 4 5 6 7 8 9 | UPDATE mytable SET myfield = CASE other_field WHEN 1 THEN 'value' WHEN 2 THEN 'value' WHEN 3 THEN 'value' END From mytable Join otherTable on otherTable.id = mytable.id Where othertable.somecolumn = '1234' |
更多备选方案:http://www.karlrixon.co.uk/writing/update-multiple-rows-with-different-values-and-a-single-sql-query/
似乎SQL Server 2012也可以处理Teradata的旧更新语法:
1 2 3 4 5 6 | UPDATE a SET a.CalculatedColumn= b.[Calculated Column] FROM table1 a, table2 b WHERE b.[common field]= a.commonfield AND a.BatchNO = '110' |
如果我没记错的话,2008R2在我尝试类似的查询时出错了。
我发现将一个更新转换成一个select来获取要在更新之前作为测试更新的行是很有用的。如果我可以选择我想要的确切行,我可以只更新那些我想要更新的行。
1 2 3 4 5 6 7 8 9 10 11 12 13 | DECLARE @expense_report_id AS INT SET @expense_report_id = 1027 --UPDATE expense_report_detail_distribution --SET service_bill_id = 9 SELECT * FROM expense_report_detail_distribution erdd INNER JOIN expense_report_detail erd INNER JOIN expense_report er ON er.expense_report_id = erd.expense_report_id ON erdd.expense_report_detail_id = erd.expense_report_detail_id WHERE er.expense_report_id = @expense_report_id |
我也有同样的问题……您不需要添加物理列。因为现在你必须维护它。您可以在选择查询中添加一个通用列:
前任:
1 2 3 4 5 6 | select tb1.col1, tb1.col2, tb1.col3 , ( select 'Match' from table2 as tbl2 where tbl1.col1 = tbl2.col1 and tab1.col2 = tbl2.col2 ) from myTable as tbl1 |
另一种方法是使用合并
1 2 3 4 5 6 7 8 9 10 | ;WITH cteTable1(CalculatedColumn, CommonField) AS ( select CalculatedColumn, CommonField from Table1 Where BatchNo = '110' ) MERGE cteTable1 AS target USING (select"Calculated Column","Common Field" FROM dbo.Table2) AS source ("Calculated Column","Common Field") ON (target.CommonField = source."Common Field") WHEN MATCHED THEN UPDATE SET target.CalculatedColumn = source."Calculated Column"; |
-合并是SQL标准的一部分
-另外,我很确定内部连接更新是不确定的。这里有个类似的问题,答案是什么?http://ask.sqlservercentral.com/questions/19089/updating-two-tables-using-single-query.html
尝试:
1 2 3 4 5 | UPDATE table1 SET CalculatedColumn = ( SELECT [Calculated Column] FROM table2 WHERE table1.commonfield = [common field]) WHERE BatchNO = '110' |