INLINE TABLE-VALUED
Translation reference to convert SQL Server UDF (User Defined Functions) with TABLE return type to Snowflake.
Description
Inline Table-Valued functions are table expression that can accept parameters, perform a SELECT statement and return a TABLE (SQL Server Language Reference Creating an inline table-valued function).
SQL Server Syntax
-- Transact-SQL Inline Table-Valued Function Syntax
CREATE [ OR ALTER ] FUNCTION [ schema_name. ] function_name
( [ { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type
[ = default ] [ READONLY ] }
[ ,...n ]
]
)
RETURNS TABLE
[ WITH <function_option> [ ,...n ] ]
[ AS ]
RETURN [ ( ] select_stmt [ ) ]
[ ; ]
Snowflake SQL Syntax
CREATE OR REPLACE FUNCTION <name> ( [ <arguments> ] )
RETURNS TABLE ( <output_col_name> <output_col_type> [, <output_col_name> <output_col_type> ... ] )
AS '<sql_expression>'sql
Sample Source Patterns
The following section describes all the possible source code patterns that can appear in this kind of CREATE FUNCTION
syntax.
For Inline Table-Valued functions, there can only exist one statement per body that could be:
SELECT
StatementWITH
Common Table Expression
Select and return values directly from one table
This is the simplest scenario, performing a simple select from a table and returning those values
SQL Server
CREATE FUNCTION GetDepartmentInfo()
RETURNS TABLE
AS
RETURN
(
SELECT DepartmentID, Name, GroupName
FROM HumanResources.Department
);
GO
SELECT * from GetDepartmentInfo()
Snowflake SQL
CREATE OR REPLACE FUNCTION GetDepartmentInfo ()
RETURNS TABLE(
DepartmentID STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN DepartmentID WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
Name STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN Name WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
GroupName STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN GroupName WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
AS
$$
SELECT
CAST(DepartmentID AS STRING),
CAST(Name AS STRING),
CAST(GroupName AS STRING)
FROM
HumanResources.Department
$$;
SELECT
*
from
TABLE(GetDepartmentInfo());
Select and return values from multiple tables renaming columns and using built in functions
This is an example of a query using built-in functions in a select statement getting data from different tables, renaming columns and returning a table.
SQL Server
CREATE FUNCTION GetPersonBasicInfo()
RETURNS TABLE
AS
RETURN
(
SELECT TOP (20)
P.PersonType,
P.FirstName,
E.JobTitle,
E.Gender,
YEAR(E.HireDate) as HIREYEAR
FROM
Person.Person P
INNER JOIN
HumanResources.Employee E
ON
P.BusinessEntityID = E.BusinessEntityID
);
GO
SELECT * FROM GetPersonBasicInfo();
Snowflake SQL
CREATE OR REPLACE FUNCTION GetPersonBasicInfo ()
RETURNS TABLE(
PersonType STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN PersonType WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
FirstName STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN FirstName WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
JobTitle STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN JobTitle WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
Gender STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN Gender WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
HIREYEAR INTEGER
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
AS
$$
SELECT
TOP 20
CAST(P.PersonType AS STRING),
CAST(P.FirstName AS STRING),
CAST(E.JobTitle AS STRING),
CAST(E.Gender AS STRING),
YEAR(E.HireDate :: TIMESTAMP) as HIREYEAR
FROM
Person.Person P
INNER JOIN
HumanResources.Employee E
ON P.BusinessEntityID = E.BusinessEntityID
$$;
SELECT
*
FROM
TABLE(GetPersonBasicInfo());
Select columns using WITH statement
The body of an inline table-valued function can also be specified using a WITH statement as shown below.
SQL Server
CREATE FUNCTION GetMaritalStatusByGender
(
@P_Gender nchar(1)
)
RETURNS TABLE
AS
RETURN
(
WITH CTE AS
(
SELECT BusinessEntityID, MaritalStatus, Gender
FROM HumanResources.Employee
where Gender = @P_Gender
)
SELECT
MaritalStatus, Gender, CONCAT(P.FirstName,' ', P.LastName) as Name
FROM
CTE INNER JOIN Person.Person P
ON
CTE.BusinessEntityID = P.BusinessEntityID
);
GO
select * from GetMaritalStatusByGender('F');
Snowflake SQL
CREATE OR REPLACE FUNCTION GetMaritalStatusByGender
(P_GENDER STRING
)
RETURNS TABLE(
MaritalStatus STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN MaritalStatus WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
Gender STRING /*** SSC-FDM-TS0012 - INFORMATION FOR THE COLUMN Gender WAS NOT FOUND. STRING DATATYPE USED TO MATCH CAST AS STRING OPERATION ***/,
Name VARCHAR
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
AS
$$
--** SSC-PRF-TS0001 - PERFORMANCE WARNING - RECURSION FOR CTE NOT CHECKED. MIGHT REQUIRE RECURSIVE KEYWORD **
WITH CTE AS
(
SELECT
BusinessEntityID,
MaritalStatus,
Gender
FROM
HumanResources.Employee
where
Gender = :P_GENDER
)
SELECT
CAST(MaritalStatus AS STRING),
CAST(Gender AS STRING),
CONCAT(P.FirstName,' ', P.LastName) as Name
FROM
CTE
INNER JOIN
Person.Person P
ON CTE.BusinessEntityID = P.BusinessEntityID
$$;
select
*
from GetMaritalStatusByGender('F') !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'TableValuedFunctionCall' NODE ***/!!!;
Known issues
No issues were found
Related EWIs
SSC-FDM-TS0012: Information for the expression was not found. CAST to STRING used
SSC-PRF-TS0001: Performance warning - recursion for CTE not checked. Might require a recursive keyword.
SSC-EWI-0073: Pending Functional Equivalence Review
Last updated