MySQL 错误 1241：操作数应包含 1 列
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MySQL error 1241: Operand should contain 1 column(s)
提问by Kumaran Senapathy
I am trying to Insert data from a table1 into table2
我正在尝试将 table1 中的数据插入 table2
insert into table2(Name,Subject,student_id,result)
select (Name,Subject,student_id,result)
from table1;
Key for table2 is student_id.
table2 的键是 student_id。
Assume that there are not any duplicates.
假设没有任何重复。
I get the error: MySQL error 1241: Operand should contain 1 column(s)
我收到错误： MySQL error 1241: Operand should contain 1 column(s)
There are only four columns in table2.
表 2 中只有四列。
回答by David
Syntax error, remove the ( )from select.
语法错误，删除( )from select。
insert into table2 (name, subject, student_id, result)
select name, subject, student_id, result
from table1;
回答by fthiella
Just remove the (and the )on your SELECT statement:
只是删除(和)你的SELECT语句：
insert into table2 (Name, Subject, student_id, result)
select Name, Subject, student_id, result
from table1;
回答by David A. Gray
Another way to make the parser raise the same exception is the following incorrect clause.
使解析器引发相同异常的另一种方法是以下不正确的子句。
SELECT r.name
FROM roles r
WHERE id IN ( SELECT role_id ,
system_user_id
FROM role_members m
WHERE r.id = m.role_id
AND m.system_user_id = intIdSystemUser
)
The nested SELECTstatement in the INclause returns two columns, which the parser sees as operands, which is technically correct, since the id column matches values from but one column (role_id) in the result returned by the nested select statement, which is expected to return a list.
子句中的嵌套SELECT语句IN返回两列，解析器将其视为操作数，这在技术上是正确的，因为 id 列仅匹配嵌套 select 语句返回的结果中的一列 (role_id) 中的值，该语句预期返回一个列表。
For sake of completeness, the correct syntax is as follows.
为完整起见，正确的语法如下。
SELECT r.name
FROM roles r
WHERE id IN ( SELECT role_id
FROM role_members m
WHERE r.id = m.role_id
AND m.system_user_id = intIdSystemUser
)
The stored procedure of which this query is a portion not only parsed, but returned the expected result.
此查询所在的存储过程不仅被解析，而且返回了预期的结果。
