On Wed, Dec 12, 2007 at 05:11:43PM -0800, Ed Reed wrote:
> I've found a glaring problem with the latest ODBC connector. Data
> types have been changed and data is no longer being read correctly.

That's not quite correct -- data types are now actually being read
correctly. They were wrong before, even if it was what you expected.

> I'm running MySQL 5.1.16 on Netware. My apps are VB6 and VBA using
> ADO. The following query produces different data types depending on
> the version of the ODBC driver.
>
> SELECT ConCat(21000,'-','a')
>
> In 3.51.19 it is a VarChar and in 3.51.22 it's a VarBinary. Concat is
> supposed to return a string. In C a byte array may be fine but in VB a
> string should be a VarChar.
>
> Is this a bug or is there a server or OBDC setting that can be changed
> to make sure that it always returns a VarChar

CONCAT() derives its return types from its arguments. The key part from
the CONCAT() documentation is:

If all arguments are non-binary strings, the result is a non-binary
string. If the arguments include any binary strings, the result is a
binary string. A numeric argument is converted to its equivalent binary
string form; if you want to avoid that, you can use an explicit type
cast, as in this example:

SELECT CONCAT(CAST(int_col AS CHAR), char_col);

That earlier releases of the driver would return a non-binary string in
your case was a bug.

That a numeric argument is converted to a binary string is an
unfortunate server "feature". I hope it will get fixed in a future
server release, but I'm not sure when that will be, and it will almost
certainly not be in the 5.1 series.

Jim