MySQL-过滤子查询中的联合

Question

I'm able to run the following:

SELECT * FROM t1 WHERE t1.id NOT IN (SELECT id FROM t2);

As well as:

SELECT * FROM (SELECT id FROM t2 UNION SELECT id FROM t3);

But MySQL complains when I attempt to run the following:

SELECT * FROM t1 WHERE t1.id NOT IN (SELECT id FROM t2 UNION SELECT id FROM t3);

The error is "unexpected 'SELECT'" for the third select. Is something wrong with my syntax? Is this not possible? I'm open to rewriting using EXISTS if that's the only way.

Answer 1

They are not mistakes on your query:

SQL Fiddle

MySQL 5.6 Schema Setup :

create table t1 ( id int );
create table t2 ( id int );
create table t3 ( id int );

insert into t1 values (1);
insert into t2 values (2);
insert into t3 values (3);

Query 1 :

SELECT * FROM t1 WHERE t1.id NOT IN
(SELECT id FROM t2 UNION SELECT id FROM t3)

Results :

| id |
|----|
|  1 |