sql MS SQL用户定义的函数语法

Posted 2021-05-13

-- Scalar function syntax
CREATE|ALTER FUNCTION [ schema_name. ] function_name   
( [ { @param_name [ AS ]
          [ type_schema_name. ] param_data_type   
    [ = default ] [ READONLY ] }   
    [ ,...n ]  
  ]  
)  
RETURNS return_data_type  
    [ WITH <function_option> [ ,...n ] ]  
    [ AS ]  
    BEGIN   
        function_body   
        RETURN scalar_expression  
    END  
[ ; ]  


-- Table-Valued function syntax
CREATE|ALTER FUNCTION [ schema_name. ] function_name   
( [ { @param_name [ AS ]
        [ type_schema_name. ] param_data_type   
    [ = default ] [ READONLY ] }   
    [ ,...n ]  
  ]  
)  
RETURNS TABLE  
    [ WITH <function_option> [ ,...n ] ]  
    [ AS ]  
    RETURN [ ( ] select_stmt [ ) ]  
[ ; ]