Convert from varchar to decimal

Here’s a way to convert a VARCHAR to DECIMAL, wrap the CONVERT in a CASE and IsNumeric function to make sure that it doesn’t cause errors when the varchar data is non-numeric

DECLARE @test VARCHAR(25)

--Numeric
SET @test = '2.55'
SELECT CONVERT(DECIMAL(3,2), CASE WHEN ISNUMERIC(@test) = 1 THEN @test ELSE '0' END)

--Non-Numeric
SET @test = 'Bob'
SELECT CONVERT(DECIMAL(3,2), CASE WHEN ISNUMERIC(@test) = 1 THEN @test ELSE '0' END)

Results
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2.55

—————————————
0.00