Implicit cast is forbidden

[cmorel]

Hi,
I have noticed that implicit casts are allowed according to the actual data in a column.
Here is an example:

SELECT * FROM MyTable WHERE MyColumn = 3897

MyColumn is defined as nvarchar(15) not null in the database schema.

This query will work only if there are no record in MyTable for which MyColumn has an alphanumerical value. Otherwise it will raise an error:

Serveur : Msg 245, Niveau 16, État 1, Ligne 1
Syntax error converting the nvarchar value 'C061' to a column of data type int.

Of course, the following query is always successful:

SELECT * FROM MyTable WHERE MyColumn = '3897'

Am I correct?


Thanks a lot.

[rmiao]

You are right.

[russellb]

MSDN Cast and Convert shows what can and cannot be converted and discusses implicit conversions.

[cmorel]

Thanks a lot for your answers.