Select query returns 0 for calculating percentage using division operator

This is because of the integer division. You can cast one of the operands to DECIMAL with correct precision, or simply
do something like this:

SELECT (group_total * 1.0/total) * 100 FROM transfer_out_summary;

Cast example:

SELECT (group_total / CAST(total AS DECIMAL(10, 2))) * 100 FROM transfer_out_summary;

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Plamen Ratchev
http://www.SQLStudio.com