执行SQL中只存在一个

Question

我正在通过Oracle DB创建iReport报告.我必须根据这样的条件选择一些值:

AND EXISTS (SELECT 1 FROM TABLE_1 WHERE x = y)  
OR EXISTS (SELECT 1 FROM TABLE_2 WHERE z = y) 

只有当第一个EXISTS为假时才能执行第二个EXISTS吗？

Answer 1

尝试在括号中使用您的条件:

AND (
        EXISTS (SELECT 1 FROM TABLE_1 WHERE x = y)  
     OR EXISTS (SELECT 1 FROM TABLE_2 WHERE z = y)
    )