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When to use CREATE FUNCTION statement in MySQL?
To associate the routine explicitly with a given database, specify the name as db_name.sp_name when you create it. The CREATE FUNCTION statement is also used in MySQL to support loadable functions. See Section 13.7.3.1, “CREATE FUNCTION Statement for Loadable Functions”. A loadable function can be regarded as an external stored function.
How to declare a named error in MySQL?
Fortunately, MySQL provides you with the DECLARE CONDITION statement that declares a named error condition, which associates with a condition. Here is the syntax of the DECLARE CONDITION statement: The condition_value can be a MySQL error code such as 1146 or a SQLSTATE value. The condition_value is represented by the condition_name .
What kind of error handling does MySQL do?
MySQL provides an easy way to define handlers that handle from general conditions such as warnings or exceptions to specific conditions e.g., specific error codes.
How to invoke a stored function in MySQL?
See Section 9.2.5, “Function Name Parsing and Resolution”, for the rules describing how the server interprets references to different kinds of functions. To invoke a stored procedure, use the CALL statement (see Section 13.2.1, “CALL Statement” ). To invoke a stored function, refer to it in an expression.
Which is an example of a stored function in MySQL?
Let’s take the example of creating a stored function. We will use the customers table in the sample database for the demonstration. The following CREATE FUNCTION statement creates a function that returns the customer level based on credit:
How to create procedure and create function in MySQL?
The following example shows a simple stored procedure that, given a country code, counts the number of cities for that country that appear in the city table of the world database. The country code is passed using an IN parameter, and the city count is returned using an OUT parameter: