MySql Where-Subquery语法错误

Question

这段代码在我有更多经验的 Sqlite 中工作。我不知道这里出了什么问题。如果它有帮助，SELECT 1 FROM Post WHERE body = 'a'; 不会给我语法错误，但这确实是

select 1 WHERE NOT EXISTS (SELECT 1 FROM Post WHERE body = 'a' ) ;

代码:

INSERT INTO `Post` (
`name`,
...
`date`) select 
@0,
...
@6 WHERE NOT EXISTS (SELECT 1 FROM Post WHERE body =  @7 ) 

错误

near 'WHERE NOT EXISTS (SELECT 1 FROM Post WHERE body =  'text' )' at line 15

Answer 1

尝试在您的选择中使用 dual 作为虚拟表(参见 here)。

INSERT INTO `Post` (
`name`,
...
`date`) select 
@0,
...
@6 
FROM DUAL
WHERE NOT EXISTS (SELECT 1 FROM Post WHERE body =  @7 ) 

来自引用的链接:

You are allowed to specify DUAL as a dummy table name in situations where no tables are referenced:

mysql> SELECT 1 + 1 FROM DUAL; -> 2