It means that the calling program may pass the argument, and the stored procedure can modify the INOUT parameter, and pass the new value back to the calling program. INOUT parametersĪn INOUT parameter is a combination of IN and OUT parameters. Notice that the stored procedure cannot access the initial value of the OUT parameter when it starts. The value of an OUT parameter can be changed inside the stored procedure and its new value is passed back to the calling program. In other words, the stored procedure only works on the copy of the IN parameter. It means that even you change the value of the IN parameter inside the stored procedure, its original value is unchanged after the stored procedure ends. In addition, the value of an IN parameter is protected. When you define an IN parameter in a stored procedure, the calling program has to pass an argument to the stored procedure. A parameter in a stored procedure has one of three modes: IN,OUT, or INOUT. CASE statement introduce you to the CASE statements including simple CASE and searched CASE statements. Conditional Statements IF statement show you how to use the IF THEN statement in stored procedures. The parameters make the stored procedure more useful and reusable. Listing stored procedures provide you with some useful commands to list stored procedures from databases. Often, stored procedures have parameters. Introduction to MySQL stored procedure parameters However, if you enter the command without the WHERE or LIKE clause, you may get hundreds of lines of output with unnecessary information.Summary: in this tutorial, you will learn how to create stored procedures with parameters, including IN, OUT, and INTOUT parameters. MySQL provides us with the SHOW PROCEDURE STATUS statement to display information about stored procedures. Creating the Stored Procedure in MySQL Now, we will create a stored procedure that will return the label numbers whose last transaction date is passed as the parameter to the GetLabelsOfLastTransDate procedure. It will help you to get all the necessary information that you should know about stored procedures. If you are new to the stored procedure topic then you can read our detailed guide on introduction to the stored procedure. However, MySQL does provide the SHOW PROCEDURE STATUS statement to list all the stored procedures from the databases. Unlike triggers where you can list all the triggers using the SHOW TRIGGERS statement, you can’t list all the stored procedures using a specific statement. Here we go! Introduction and Prerequisites We will see both ways through examples and proper snapshots. When you write your stored procedure in SQL, you know that it will run on every platform that MySQL runs on, without obliging you to install an additional runtime-environment package, or set permissions for program execution in the operating system, or deploy different packages if you have different computer types. There are two ways you can list the procedures and functions in MySQL. Thus, it allows you to pass the same statements multiple times, thereby, enabling reusability. Based on the statements in the procedure and the parameters you pass, it can perform one or multiple DML operations on the database, and return value, if any. It is a super simple tutorial and we will make it more effective by using multiple examples. A stored procedure in SQL is a group of SQL statements that are stored together in a database. Stored procedures enable SQL code to be reused as often as needed, helping to simplify application development and reduce statement errors. In this tutorial, we will learn how to list stored procedures in the MySQL database. MySQL stored procedures also support the use of input and output parameters, making them a highly flexible tool for encapsulating statement logic.
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