如何在条件语句中设置 LIMIT；后置数据库

Question

我想按id降序排列结果，然后根据@condition限制获得的行数

ORDER BY id DESC
IF @condition is TRUE THEN  LIMIT 1
ELSE nothing
END IF

Answer 1

您可以使用 CASE:

ORDER BY id DESC
LIMIT CASE WHEN @condition THEN 1 END;

LIMIT NULL 等同于省略 LIMIT 子句

How to set LIMIT within a conditional statement; POSTGRESQL