SQL INSERT INTO结合值和选择失败

Question

I wanted to insert two values, one is filled by a fixed number and the other one is the id from another table.

Now I got the error

#1242 - Subquery returns more than 1 row.

INSERT INTO table1 (value1, value2) VALUES 
(6 , (SELECT id FROM table2 WHERE name = 'Peter'))

Maybe you can help me.

Answer 1

If you want to insert record into your table1 for every record in table2 where name is Peter this approach should work.

This insert query will insert all records from table2 where name is "Peter" into table1. If you want to insert only one record you could use LIMIT as Macmee has explained in his answer

insert into dbo.table1
(
     value1,
     value2
)(
     select 
          6,
          table2.id 
     from 
          table2
     where
          name = 'Peter'
)

Answer 2

try using LIMIT 1 :

INSERT INTO table1 (value1, value2) VALUES (6 , (SELECT id FROM table2 WHERE name = 'Peter' LIMIT 1))

This way in your nested query (SELECT id FROM table2 WHERE name = 'Peter' LIMIT 1) it will only return the first match, and your insert should go through.

Keep in mind that if your intent was to insert new rows for EVERY row in table2 who's name is "Peter" then this will only insert the first one.