MySQL Stored Procedure Learning

1. Stored Procedure syntax
   Create procedure proc_name ([in | Out | inout] Param data type)
   Begin
   Statement
   End

   In the MySQL command line, each statement must be separated by a semicolon (semicolon), which is the execution point of MySQL. In order to write the stored procedure, use the delimiter // command to convert the separator //.
   Delimiter //

2. Write a simple procedure
   Mysql-> Create procedure Hello ()
   -> Begin
   -> Select "Hello world! ";
   -> End
   -> //

Query OK, 0 rows affected (0.00 Sec)

3. Call stored procedure: Call proc_name
   Mysql-> call Hello ()//
   + ---------------------- +
   | It is a hello World. |
   + ---------------------- +
   | It is a hello World. |
   + ---------------------- +
   1 row in SET (0.00 Sec)
4. Delete stored procedure
   Drop proc_name
   Note: A stored procedure can call another stored procedure, but cannot be deleted.