Operand shoshould contain 1 column (s), operandcontain
This error was found during the SQL test today: Operand shoshould contain 1 column (s ).
The reason is that there are multiple fields behind the in condition, and there can only be one field behind the in condition.
The subquery in the right brace of the IN predicate can only output one field, but your subquery uses the symbol "*". IN this way, the database engine will output all fields IN the es_message table to the brackets on the right of the IN, and of course an error will be reported.
Correction Method: Specify only one field to be compared after the SELECT statement of the subquery.
SQL statement error: Prompt: "#1241-Operand shoshould contain 1 column (s)" error
SELECT * FROM ies_message where msgsendtype = 2
Which columns are queried,
Msgsendtype IN can be followed by only one column.