Similar to the simple CASE statement, if you don’t specify an ELSE clause and no condition is TRUE, MySQL raises the same error: Case not found for CASE statement Code language: PHP ( php ) If no search_condition evaluates to TRUE, the CASE will execute else-statements in the ELSE clause if an ELSE clause is available. In this syntax, searched CASE evaluates each search_condition in the WHEN clause until it finds a condition that evaluates to TRUE, then it executes the corresponding THEN clause statements. Here is the basic syntax of the searched CASE statement: CASE The searched CASE statement is equivalent to the IF statement, however, it’s much more readable than the IF statement. To perform more complex matches such as ranges, you use the searched CASE statement. The simple CASE statement only allows you to compare a value with a set of distinct values. This statement calls the stored procedure with the customer id 112 and returns the shipping information: CALL GetCustomerShipping( Code language: SQL (Structured Query Language) ( sql )ġ row in set ( 0.00 sec) Code language: SQL (Structured Query Language) ( sql ) Searched CASE statement The following flowchart demonstrates the logic of the CASE statement for determining the shipping time: The customers from other countries have 5-day shipping. If the customer locates in Canada, the shipping time is 3-day shipping. If the customer locates in USA, the shipping time is 2-day shipping. Second, use the simple CASE statement to determine the shipping time based on the country of the customer. The GetCustomerShipping() stored procedure accepts two parameters: pCustomerNumber as an IN parameter and pShipping as an OUT parameter.įirst, select the country of the customer from the customers table by the input customer number. The following stored procedure illustrates how to use the simple CASE statement: DELIMITER $$ The simple CASE statement tests for equality ( =), you cannot use it to test equality with NULL because NULL = NULL returns FALSE. To avoid the error when the case_value does not equal any when_value, you can use an empty BEGIN.END block in the ELSE clause, as follows: CASE case_value The statements can consist of one or more SQL statements and cannot be empty. Notice that the case_value can be a literal value or an expression. When the ELSE clause does not exist and the CASE cannot find any when_value equal to the case_value, it issues an error: Case not found for CASE statement Code language: PHP ( php ) If CASE statement cannot find any when_value equal to the case_value, it executes the else-statements in the ELSE clause if the ELSE clause is provided. ![]() ![]() When the CASE finds a case_value equal to a when_value, it executes statements in the corresponding THEN clause. In this syntax, the simple CASE statement sequentially compares the case_value is with when_value1, when_value2, and so on until it finds a match. The following is the basic syntax of the simple CASE statement: CASE case_valueĮND CASE Code language: SQL (Structured Query Language) ( sql ) Note that if you want to add the if-else logic to an SQL statement, you use the CASE expression which differs from the CASE statement described in this tutorial. The CASE statement has two forms: simple CASE and searched CASE statements. The CASE statements make the code more readable and efficient. Introduction to MySQL CASE statementīesides the IF statement, MySQL provides an alternative conditional statement called the CASE statement for constructing conditional statements in stored procedures. I also edited the comments, as the logic was reversed in those, which again may have beed cause for confusion, or caused by confision.Summary: in this tutorial, you will learn how to use MySQL CASE statements to construct complex conditional statements inside stored procedures. This is a revised version of the example gave, with isset swapped for empty and trim. When I check the second radio button without dates or with dates in either input field or both I eitherget 2 as output or all - which is the default of the switch When I check it I get wrong input from the first div in the form, the period div ![]()
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