![]() If the IF NOT EXISTS clause is used, MariaDB will return a warning instead of an error if the function already exists. If you declare a deterministic function as NOT DETERMINISTIC, in some cases the queries will be slower. If you declare a non-deterministic function as DETERMINISTIC, you may get incorrect results. If you want to explicitly state that the function is not deterministic (which is the default) you can use the NOT DETERMINISTIC keywords. In such cases, you should declare the routine using the DETERMINISTIC keyword. The optimizer may choose a faster execution plan if it known that the function is deterministic. Also, a function is non-deterministic if it uses non-deterministic functions like NOW() or CURRENT_TIMESTAMP(). If the result may be affected by stored data, server variables, random numbers or any value that is not explicitly passed, then the function is not deterministic. However that clause has no meaning, because SQL is the only supported language for stored functions.Ī function is deterministic if it can produce only one result for a given list of parameters. LANGUAGE SQL is a standard SQL clause, and it can be used in MariaDB for portability. Time a routine is created, and always executes the routine with this setting inįorce, regardless of the server SQL mode in effect when the routine is invoked. MariaDB stores the SQL_MODE system variable setting that is in effect at the Specifies an ENUM or SET value in the RETURNS clause, but the RETURNĬlause returns an integer, the value returned from the function is the string for the corresponding ENUM Otherwise, the value is coerced to the proper type. If the SQL_MODE is strict (STRICT_ALL_TABLES or STRICT_TRANS_TABLES flags are specified), a 1366 error will be produced. What happens if the RETURN clause returns a value of a different type? It depends on the SQL_MODE in effect at the moment of the function creation. NULL values are permitted with all return types. The RETURNS clause specifies the return type of the function. See Stored Aggregate Functions for details. SET 4186 (HY000): OUT or INOUT argument 3 for function add_func3 is not allowed hereĬREATE FUNCTION add_func4(IN a INT, IN b INT, d INT) RETURNS INTįrom MariaDB 10.3.3, it is possible to create stored aggregate functions as well. DELIMITER $$ĬREATE FUNCTION add_func3(IN a INT, IN b INT, OUT c INT) RETURNS INT This allows functions to be more complex and nested. These quantifiers are especially useful for creating functions with more than one return value. OUT, INOUT and its equivalent IN OUT, are only valid if called from SET and not SELECT. Prior to 10.8.0 quantifiers were supported only in procedures. The function parameter qualifiers for IN, OUT, INOUT, and IN OUT were added in a 10.8.0 preview release. Parameter names are not case sensitive.Įach parameter can be declared to use any valid data type, except thatįor valid identifiers to use as function names, see Identifier Names. If there are no parameters, an empty parameter list of () should be The parameter list enclosed within parentheses must always be present. Use the fully qualified name when you call it. If the function name is the same as the name of a built-in function, you must With a given database, specify the fully-qualified name as db_name. When the function isĬalled, the RETURN statement immediately returns its result, and any statements after RETURNīy default, a function is associated with the current database. The compound statement must contain a RETURN statement. You can also replace the RETURN clause with a BEGIN.END compound Use a LIMIT clause to ensure only one row is returned. If more than one row is returned when the function is called, error 1242 If more than one column is returned when the function is called,Įrror 1241 results. Parentheses, exactly as you would to use a subselect for any other expression. You can use a SELECT statement for the function body by enclosing it in You can also use a variant of the CREATE FUNCTION statement to install a user-definedįunction (UDF) defined by a plugin. See Security below for details on privileges. If you have the appropriate privileges, you can call the function exactly as you Theįunction body can be any valid SQL expression as you would use, for example, in any selectĮxpression. The CREATE ROUTINE database privilege to use CREATE FUNCTION.Ī function takes any number of arguments and returns a value from the function body. Use the CREATE FUNCTION statement to create a new stored function.
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