Presentations & Meeting Supplies

query not working
$query: select * from SKU_CATALOG, SKU_GROUP, SUB_SECTION where (SKU_CATALOG.CAT_ID = '0039') and SKU_CATALOG.SKU_GP_ID = SKU_GROUP.SKU_GP_ID and SKU_CATALOG.SUB_SECT_ID = SUB_SECTION.SUB_SECT_ID and SUB_SECTION.SECT_ID = '138' and `` = '12' limit 12
error: Unknown column '' in 'where clause'