Then again, there's always some schmo that's going to come along and try to beat it.

SELECT TestNum, Jeff=CASE

WHEN FLOOR(REVERSE(ABS(TestNum))) = 0.0

THEN 0

ELSE FLOOR(LOG10(REVERSE(ABS(TestNum)))+1) END

,Markus=CASE

WHEN FLOOR(LOG10(REVERSE(ABS(TestNum)+1)))+1 < 0

THEN 0 ELSE FLOOR(LOG10(REVERSE(ABS(TestNum)+1)))+1 END

,Dwain=CASE

WHEN FLOOR(TestNum) = TestNum THEN 0

ELSE LEN(CAST(REVERSE(ABS(TestNum) % 1) AS DECIMAL(38,0))) END

,DwainRedux=CASE

WHEN FLOOR(TestNum) = TestNum THEN 0

ELSE LEN(CAST(REVERSE(TestNum - CAST(FLOOR(TestNum) AS DECIMAL)) AS DECIMAL)) END

FROM (

SELECT CAST(99 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.1 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.11 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.1111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.11111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.111111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(-99.11111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(-99.111111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(99.1111111111111111 AS DECIMAL(38,15))

UNION ALL SELECT CAST(0.1 AS DECIMAL(38,15))) Nums(TestNum)

CREATE TABLE #BigNums (TestNum DECIMAL(38,15))

INSERT INTO #BigNums

SELECT 1.* CHECKSUM(NEWID()) / POWER(10, ABS(CHECKSUM(NEWID())) % 10)

FROM (

SELECT TOP 1000000 1

FROM sys.all_columns a, sys.all_columns b

)Tally(n)

DECLARE @Hold DECIMAL(38,15)

PRINT 'Jeff'

SET STATISTICS TIME ON

SELECT @Hold=CASE

WHEN FLOOR(REVERSE(ABS(TestNum))) = 0.0

THEN 0

ELSE FLOOR(LOG10(REVERSE(ABS(TestNum)))+1)

END

FROM #BigNums

SET STATISTICS TIME OFF

PRINT 'Markus'

SET STATISTICS TIME ON

SELECT @Hold=CASE

WHEN FLOOR(LOG10(REVERSE(ABS(TestNum)+1)))+1 < 0

THEN 0 ELSE FLOOR(LOG10(REVERSE(ABS(TestNum)+1)))+1 END

FROM #BigNums

SET STATISTICS TIME OFF

PRINT 'Dwain'

SET STATISTICS TIME ON

SELECT @Hold=CASE

WHEN FLOOR(TestNum) = TestNum THEN 0

ELSE LEN(CAST(REVERSE(ABS(TestNum) % 1) AS DECIMAL(38,0))) END

FROM #BigNums

SET STATISTICS TIME OFF

PRINT 'Dwain Redux'

SET STATISTICS TIME ON

SELECT @Hold=CASE

WHEN FLOOR(TestNum) = TestNum THEN 0

ELSE LEN(CAST(REVERSE(TestNum - CAST(FLOOR(TestNum) AS DECIMAL)) AS DECIMAL)) END

FROM #BigNums

SET STATISTICS TIME OFF

PRINT 'Jeff - Revised WHEN'

SET STATISTICS TIME ON

SELECT @Hold=CASE

WHEN FLOOR(TestNum) = TestNum

THEN 0

ELSE FLOOR(LOG10(REVERSE(ABS(TestNum)))+1)

END

FROM #BigNums

SET STATISTICS TIME OFF

DROP TABLE #BigNums

Latest speed results:

Jeff

SQL Server Execution Times:

CPU time = 3338 ms, elapsed time = 3408 ms.

Markus

SQL Server Execution Times:

CPU time = 4337 ms, elapsed time = 4369 ms.

Dwain

SQL Server Execution Times:

CPU time = 2012 ms, elapsed time = 2071 ms.

Dwain Redux

SQL Server Execution Times:

CPU time = 1888 ms, elapsed time = 1928 ms.

Jeff - Revised WHEN

SQL Server Execution Times:

CPU time = 2293 ms, elapsed time = 2362 ms.

It appears that most of the speed boost was a result of the revision to the WHEN clause.