SET FMTONLY (Transact-SQL)

APPLIES TO: yesSQL Server yesAzure SQL Database yesAzure SQL Data Warehouse yesParallel Data Warehouse

Returns only metadata to the client. Can be used to test the format of the response without actually running the query.

Topic link icon Transact-SQL Syntax Conventions

Syntax

SET FMTONLY { ON | OFF }   

Remarks

When FMTONLY is ON, a rowset is returned with the column names, but without any data rows.

SET FMTONLY ON has no effect when the Transact-SQL batch is parsed. The effect occurs during execution run time.

The default value is OFF.

Permissions

Requires membership in the public role.

Examples

The following Transact-SQL code example sets FMTONLY to ON. This setting causes SQL Server to return only metadata information about the selected columns. Specifically, the column names are returned. No data rows are returned.

In the example, the test execution of stored procedure prc_gm29 returns the following:

  • Multiple rowsets.
  • Columns from multiple tables, in one of its SELECT statements.
go
SET NoCount ON;

go
DROP PROCEDURE IF EXISTS prc_gm29;

DROP Table IF EXISTS #tabTemp41;
DROP Table IF EXISTS #tabTemp42;
go

CREATE TABLE #tabTemp41
(
   KeyInt41        int           not null,
   Name41          nvarchar(16)  not null,
   TargetDateTime  datetime      not null  default GetDate()
);

CREATE TABLE #tabTemp42
(
   KeyInt42 int          not null,   -- JOIN-able to KeyInt41.
   Name42   nvarchar(16) not null
);
go

INSERT into #tabTemp41 (KeyInt41, Name41) values (10, 't41-c');
INSERT into #tabTemp42 (KeyInt42, Name42) values (10, 't42-p');
go

CREATE PROCEDURE prc_gm29
AS
begin
SELECT * from #tabTemp41;
SELECT * from #tabTemp42;

SELECT t41.KeyInt41, t41.TargetDateTime, t41.Name41, t42.Name42
   from
                 #tabTemp41 as t41
      INNER JOIN #tabTemp42 as t42 on t42.KeyInt42 = t41.KeyInt41
end;
go

SET DATEFORMAT mdy;

SET FMTONLY ON;
EXECUTE prc_gm29;   -- Returns multiple tables.
SET FMTONLY OFF;
go
DROP PROCEDURE IF EXISTS prc_gm29;

DROP Table IF EXISTS #tabTemp41;
DROP Table IF EXISTS #tabTemp42;
go

/****  Actual Output:
[C:\JunkM\]
>> osql.exe -S myazuresqldb.database.windows.net -U somebody -P secret -d MyDatabase -i C:\JunkM\Issue-2246-a.SQL 

 KeyInt41    Name41           TargetDateTime
 ----------- ---------------- -----------------------

 KeyInt42    Name42
 ----------- ----------------

 KeyInt41    TargetDateTime          Name41           Name42
 ----------- ----------------------- ---------------- ----------------


[C:\JunkM\]
>>
****/

See Also

SET Statements (Transact-SQL)