Nov 23, 2011 · I'm trying to write a MySQL function with a select inside, but always get a NULL return CREATE FUNCTION test (i CHAR) RETURNS CHAR NOT DETERMINISTIC BEGIN DECLARE select_var CHAR; SET select_var =

Summary: in this tutorial, you will learn how to create a stored function using the CREATE FUNCTION statement. A stored function is a specialized type of stored program designed to return a single value.

Jan 9, 2019 · A MySQL function can only return a single value. You can use a stored procedure, instead: DELIMITER $$ CREATE PROCEDURE `getCharacters`() BEGIN SELECT * FROM `characters` WHERE `level` > 50; END $$ DELIMITER ; CALL getCharacters;

Mar 30, 2022 · Stored functions are very useful when you want to write complex business logic and return a single value. You can call the stored function from a SQL statement. For example- SELECT colName, FunName (Parameter) FROM table_name; The syntax of the MySQL stored function is very identical to the stored procedure. There are only a few differences.

Dec 15, 2021 · Try using a DECLARE and a SET to hold your SELECT Query before you return it: CREATE FUNCION whereAndWhen(species, VARCHAR(255)) RETURNS INT() BEGIN. DECLARE zoneNum INT; SET zoneNum = (SELECT animals.zone. FROM animals. WHERE animals.species = species); RETURN zoneNum; END; // You can use SELECT INTO.

Expressions can be used at several points in SQL statements, such as in the ORDER BY or HAVING clauses of SELECT statements, in the WHERE clause of a SELECT, DELETE, or UPDATE statement, or in SET statements. Expressions can be written using values from several sources, such as literal values, column values, NULL, variables, built-in functions and operators, loadable functions, and stored ...

Oct 27, 2024 · MySQL functions are pre-built routines that perform specific operations. They accept input parameters (arguments) and return a value. These functions can be used in various parts of your SQL queries, including SELECT, WHERE, ORDER BY, and more. MySQL offers a rich set of functions categorized by their purpose.

For example, select_type is DELETE for DELETE statements. table ... the value used is the result of some function. To see which function, use SHOW WARNINGS following EXPLAIN to see the extended EXPLAIN output. The function might actually be an operator such as an arithmetic operator. ... In the following examples, MySQL can use a ref join to ...

Jul 9, 2021 · In this article, I am going to discuss How to Create and Call User-Defined Functions in MySQL with examples. At the end of this article, you will understand what is a user-defined function in MySQL and how to create and use MySQL User-Defined functions with examples. What is a function in MySQL?

MySQL performs comparisons using the following rules: If one or both arguments are NULL, the result of the comparison is NULL, except for the <=> operator. If both arguments in a comparison operation are strings, they are compared as strings. If both arguments are integers, they are compared as integers.