Musíte použít dynamické sql:
set @sql = 'SELECT @cols FROM @t';
SELECT @sql := GROUP_CONCAT(REPLACE(REPLACE(@sql, @cols,
CONCAT(COLUMN_NAME, ', ', DATA_TYPE, ', ',
'MIN(', COLUMN_NAME, '), MAX(', COLUMN_NAME, ')'
)
),
@t, 'tbl_name') SEPARATOR ' union all '
)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME='tbl_name' AND DATA_TYPE = 'decimal';
prepare s from @sql;
execute s;
deallocate prepare s;