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MySQL “not a variable or NEW pseudo-variable” message. What is this error in my Stored Procedure?
To get rid of this error message, let us see a sample example. But before that let us go through the concept to fix it.
Use variable to get the value from stored procedure. The variable will prefix with @ symbol. The syntax is as follows −
CALL yourStoredProcedureName(yourParameter1,yourParameter2,..........N,@yourVariableName);
To see the value of variable you need to use select statement. The syntax is as follows −
SELECT @yourVariableName;
To understand the above syntax, let us create a table and insert some records in the table.
The query to create a table is as follows −
mysql> create table StoredProcedureDemo -> ( -> Id int, -> Name varchar(10) -> ); Query OK, 0 rows affected (1.20 sec)
Now insert some records in the table using insert command. The query is as follows −
mysql> insert into StoredProcedureDemo values(1,'John'); Query OK, 1 row affected (0.31 sec) mysql> insert into StoredProcedureDemo values(2,'Carol'); Query OK, 1 row affected (0.19 sec)
Display all records from the table using select statement. The query is as follows −
mysql> select *from StoredProcedureDemo;
The following is the output −
+------+-------+ | Id | Name | +------+-------+ | 1 | John | | 2 | Carol | +------+-------+ 2 rows in set (0.00 sec)
Here is the stored procedure that returns a value. The query is as follows to create a stored procedure −
mysql> DELIMITER // mysql> create procedure Update_table(IN Id int, IN Name VARCHAR(20),OUT message VARCHAR(50)) -> BEGIN -> set message= 'DATABASE HAS BEEN UPDATED'; -> INSERT INTO StoredProcedureDemo -> values (Id, Name); -> end; -> // Query OK, 0 rows affected (0.67 sec) mysql> DELIMITER ;
Now call the stored procedure with some values −
mysql> call Update_table(3,'Larry',@UserMessage);
Query OK, 1 row affected (0.13 sec)
Check the value of variable @UserMessage using select statement. The query is as follows −
mysql> select @UserMessage;
The following is the output −
+---------------------------+ | @UserMessage | +---------------------------+ | DATABASE HAS BEEN UPDATED | +---------------------------+ 1 row in set (0.00 sec)
Now check the table records once again. The query is as follows −
mysql> select *from StoredProcedureDemo;
The following is the output −
+------+-------+ | Id | Name | +------+-------+ | 1 | John | | 2 | Carol | | 3 | Larry | +------+-------+ 3 rows in set (0.00 sec)
Look at the above sample output, a new record with id 3 has been inserted. Now you won’t get the error message.
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