MySQL stored procedure calls each other and obtains the error code example _ MySQL

The MySQL stored procedure calls each other and obtains the error code example bitsCN.com.
Mysql>
Mysql> delimiter $
Mysql>
Mysql> create procedure myProc ()
-> MODIFIES SQL DATA
-> BEGIN
-> DECLARE l_status VARCHAR (20 );
->
-> CALL myProc1 (l_status );
-> IF l_status = 'Duplicate Entry 'THEN
-> Select concat ('Warning: using existing definition for location') AS Warning;
-> End if;
-> END $
Query OK, 0 rows affected (0.00 sec)

Mysql>
Mysql> create procedure myProc1 (OUT out_status VARCHAR (30 ))
-> BEGIN
-> Set out_status = 'Duplicate Entry ';
-> END $
Query OK, 0 rows affected (0.00 sec)

Mysql>
Mysql>
Mysql> delimiter;
Mysql> call myProc ();
+ -------------------------------------------------- +
| Warning |
+ -------------------------------------------------- +
| Warning: using existing definition for location |
+ -------------------------------------------------- +
1 row in set (0.00 sec)

Query OK, 0 rows affected (0.01 sec)

Mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)

Mysql> drop procedure myProc1;
Query OK, 0 rows affected (0.00 sec)

Mysql>
Mysql>
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