Variables are not allowed in the TABLESAMPLE or REPEATABLE clauses

Msg 497, Level 15, State 1, Line 1
Variables are not allowed in the TABLESAMPLE or REPEATABLE clauses.

The TABLESAMPLE clause, limits the number of rows returned from a table in the FROM clause to a sample number or PERCENT of rows. The syntax for the TABLESAMPLE clause is as follows:

One limitation of the TABLESAMPLE clause is that both the sample_number and repeat_seed parameters cannot be local variables; otherwise this error message is generated.

To generate the error let's see the below example.

Example:

CREATE TABLE [dbo].[CallDetailRecord] ( 
    [CallDetailRecordID]        INT NOT NULL IDENTITY(1, 1),
    [SourceNumber]              VARCHAR(30),
    [DestinationNumber]         VARCHAR(30),
    [CallTime]                  DATETIME,
    [CallDuration]              INT
)

-- Using a local variable for the sample number of rows
DECLARE @RowCount INT
SET @RowCount = 100
SELECT * FROM [dbo].[CallDetailRecord] TABLESAMPLE ( @RowCount ROWS)

Msg 497, Level 15, State 1, Line 12
Variables are not allowed in the TABLESAMPLE or REPEATABLE clauses.

-- Using a local variable for sample percentage
DECLARE @PercentSample	DECIMAL(5, 2)
SET @PercentSample = 75.0
SELECT * FROM [dbo].[CallDetailRecord] TABLESAMPLE ( @PercentSample PERCENT)

Msg 497, Level 15, State 1, Line 17
Variables are not allowed in the TABLESAMPLE or REPEATABLE clauses.

-- Using a local variable for the repeat seed
DECLARE @RepeatSeed INT
SET @RepeatSeed = 124
SELECT * FROM [dbo].[CallDetailRecord] TABLESAMPLE ( 50 PERCENT ) REPEATABLE ( @RepeatSeed )

Msg 497, Level 15, State 1, Line 22
Variables are not allowed in the TABLESAMPLE or REPEATABLE clauses.

Solution :

One way to avoid this error is not to make use of local variables when specifying the sample number of rows, the sample percentage or the repeat seed. Using the examples above, the following SELECT statement will generate the desired output:

SELECT * FROM [dbo].[CallDetailRecord] TABLESAMPLE ( 100 ROWS )
SELECT * FROM [dbo].[CallDetailRecord] TABLESAMPLE ( 75.0 PERCENT )
SELECT * FROM [dbo].[CallDetailRecord] TABLESAMPLE ( 50 PERCENT ) REPEATABLE ( 124 )

To make it dynamic it can be done in Dynamic SQL statements.

-- Using a local variable for the sample number of rows
DECLARE @RowCount INT
DECLARE @SQLStmt VARCHAR(100)
SET @RowCount = 100
SET @SQLStmt = 'SELECT * FROM [dbo].[CallDetailRecord] 
                TABLESAMPLE ( ' + CAST(@RowCount AS VARCHAR(10)) + ' ROWS )'
EXECUTE ( @SQLStmt )

Similarly other example can be done like above.