Sometimes you need to convert a datatype to a different datatype in SQL Server. The reason might be to able to compare a column with a variable or another column with a different datatype. When you convert a datatype, you can get some unexpected results, like when you convert an int to a varchar and use a shorter varchar than the value you are trying to convert. Take a look at the code below.
DECLARE @myInt INT = 1111111; SELECT ConvertedValue = CONVERT(VARCHAR(6), @myInt), OriginalValue = @myInt;
As you can see from the result, the converted value couldn’t fit in a VARCHAR(6) and you get an asterix instead. This is documented behaviour in SQL Server Books online.
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