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CHAR and VARCHAR

| Thursday, February 25, 2010
Recently I happened to find an error in the decision, which included the conversion:

     CAST(model AS VARCHAR)

Those who have studied the scheme "Computers", think about the absurdity of the type conversion in the same type (the column ‘model’ is defined as VARCHAR (50)). However, it is this conversion, and made the request wrong.

The fact is that, if the type size is not specified when converting, then SQL Server is set to defaults, which for VARCHAR are 30. Thus, if the converted string has larger size, then cut off all the characters except for the first 30. Of course, any errors will not occur. Just on the "long" model numbers the proposed decision and gave the wrong result. As they say in such cases, read the documentation. However, it is interesting that on this occasion Standard said?

Read more: SQL problem and solution

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