我问了一个问题,得到了这个有帮助的回复。
UPDATE TABLE_A a JOIN TABLE_B b
ON a.join_col = b.join_col AND a.column_a = b.column_b
SET a.column_c = a.column_c + 1
现在我希望这样做,如果有三个表涉及像这样的东西。
UPDATE tableC c JOIN tableB b JOIN tableA a
我的问题基本上是……有可能在一个UPDATE
语句上做三个表连接吗?它的正确语法是什么?我要做下面的事情吗?
JOIN tableB, tableA
JOIN tableB JOIN tableA
答案是是的,你可以。
试着这样写:
UPDATE TABLE_A a
JOIN TABLE_B b ON a.join_col = b.join_col AND a.column_a = b.column_b
JOIN TABLE_C c ON [condition]
SET a.column_c = a.column_c + 1
对于一般的更新 join:
UPDATE TABLEA a
JOIN TABLEB b ON a.join_colA = b.join_colB
SET a.columnToUpdate = [something]
实现相同结果的另一种方法是根本不使用JOIN
关键字。
UPDATE TABLE_A, TABLE_B
SET TABLE_A.column_c = TABLE_B.column_c + 1
WHERE TABLE_A.join_col = TABLE_B.join_col
下面是更新查询,其中包括JOIN
和WHERE
。同样,我们可以使用多个join/where子句:
UPDATE opportunities_cstm oc JOIN opportunities o ON oc.id_c = o.id
SET oc.forecast_stage_c = 'APX'
WHERE o.deleted = 0
AND o.sales_stage IN('ABC','PQR','XYZ')
备选方案总体方案:
UPDATE table A
JOIN table B ON {join fields}
JOIN table C ON {join fields}
JOIN {as many tables as you need}
SET A.column = {expression}
的例子:
UPDATE person P
JOIN address A ON P.home_address_id = A.id
JOIN city C ON A.city_id = C.id
SET P.home_zip = C.zipcode;
是的,您可以为更新语句执行三表连接。下面是一个例子:
UPDATE customer_table c
JOIN
employee_table e
ON c.city_id = e.city_id
JOIN
anyother_table a
ON a.someID = e.someID
SET c.active = "Yes"
WHERE c.city = "New york";
对于PostgreSQL示例:
UPDATE TableA AS a
SET param_from_table_a=FALSE -- param FROM TableA
FROM TableB AS b
WHERE b.id=a.param_id AND a.amount <> 0;
没有答案不适合我,我发现这在mysql手册
UPDATE T1,T2 INNER JOIN T2 ON T1.C1 = T2.C1 SET T1.C2 = T2.C2, T2.C3 = expr WHERE condition