Usage of call in mysql

The CALL statement in MySQL is used to call stored procedures or functions and to define predefined SQL statement groups. The steps are as follows: 1. Create a stored procedure or function; 2. Write a CALL statement, specifying the name and parameters; 3. Specify parameter values ​​that match the parameter type and order; 4. Execute the CALL statement.

Usage of CALL in MySQL

The CALL statement is used to call a stored procedure or function, and the stored procedure or function contains A set of predefined SQL statements. The syntax of the CALL statement is as follows:

<code>CALL [schema_name.]procedure_name(argument_list);</code>

Where:

• schema_name is the schema name where the stored procedure or function is located (optional)
• procedure_name is the name of the stored procedure or function
• argument_list is the parameter list of the stored procedure or function (optional)

Details below Introducing the steps to use the CALL statement:

1. Create a stored procedure or function

Before calling a stored procedure or function, you need to create it. Can be created using the CREATE PROCEDURE or CREATE FUNCTION statement.

2. Write a CALL statement

When using the CALL statement to call a stored procedure or function, you need to specify its name and parameters (if necessary).

3. Specify parameters

The stored procedure or function can accept parameters. In a CALL statement, parameter values ​​must match the parameter types and order declared in the stored procedure or function.

4. Execute the CALL statement

The CALL statement can be executed in the following ways:

• Execute at the MySQL command prompt: CALL procedure_name(argument_list);
• Executed as a SQL statement in the application

Example

The following example call name A stored procedure for get_customer_details that obtains the details of a specified customer:

<code>CALL get_customer_details(10);</code>

In the above example, 10 is the customer whose details are to be obtained ID. The stored procedure returns a result set that contains the customer's details.

Note:

• The CALL statement returns a statement completion flag indicating whether the stored procedure or function was executed successfully.
• If the stored procedure or function returns any output parameters or result sets, they can be retrieved using the SELECT statement.

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