oracle sql错误案例当其他时候(oracle sql error Case When Then Else)

oracle sql错误案例当其他时候(oracle sql error Case When Then Else) SELECT * FROM FirstTable WHERE RowProcessed = 'N' AND ( CASE WHEN EXISTS(SELECT top 1 FROM SecondTable) THEN 1 ELSE EXISTS( SELECT SecondTable.RowProcessed FROM SecondTable WHERE FirstTable.Key = SecondTable.Key AND SecondTable.RowProcessed = 'Y' ) END ) AND OtherConditions

Case当where else在where子句中。 不确定语法。

我想验证SecondTable中是否有行，如果有行检查另一个条件，那基本上就是我想要做的。

SELECT * FROM FirstTable WHERE RowProcessed = 'N' AND ( CASE WHEN EXISTS(SELECT top 1 FROM SecondTable) THEN 1 ELSE EXISTS( SELECT SecondTable.RowProcessed FROM SecondTable WHERE FirstTable.Key = SecondTable.Key AND SecondTable.RowProcessed = 'Y' ) END ) AND OtherConditions

Case When then else in where clause. Not sure about the syntax.

I would like to verify there are rows in the SecondTable and if there are rows check for another condition, that is basicallly what I want to do.

最满意答案

也许这就是你想要的？ 如果SecondTable中有行，那么执行第二个EXISTS ：

SELECT * FROM FirstTable WHERE RowProcessed = 'N' AND (NOT EXISTS (SELECT 1 from SecondTable) OR EXISTS (SELECT 1 FROM SecondTable WHERE FirstTable.Key = SecondTable.Key and SecondTable.RowProcessed = 'Y')) AND OtherConditions

Perhaps this is what you want? If there are rows in SecondTable, then do the second EXISTS:

SELECT * FROM FirstTable WHERE RowProcessed = 'N' AND (NOT EXISTS (SELECT 1 from SecondTable) OR EXISTS (SELECT 1 FROM SecondTable WHERE FirstTable.Key = SecondTable.Key and SecondTable.RowProcessed = 'Y')) AND OtherConditions