如何在SQL Server 2008 R2中将nvarchar值乘以十进制

Question

I have written this code

Qty = 5 Rate = 50.10

SELECT cast(convert(decimal, qty)+ convert(decimal, rate) as decimal)
FROM product where code='P0001'

Result = 250 it should be 250.50

Answer 1

DECLARE @QTY VARCHAR(10)
DECLARE @RATE VARCHAR(10)
SET @QTY = 5 
SET @RATE = 50.10

SELECT @QTY,@RATE 

SELECT CAST(CONVERT(DECIMAL(10,2), @QTY) * CONVERT(DECIMAL(10,2), @RATE) AS DECIMAL(10,2))

Answer 2

Changes as

SELECT cast(convert(decimal(18,2), qty)+ convert(decimal(18,2), rate) as decimal(18,2))
FROM product where code='P0001'