Updating multiple tables(3) simultaneously..

hello everyone..i have 3 tables t1,t2,t3..if i update t1,t2 and t3 must also be updated..how could i do this? i have just been tried [CODE]UPDATE t1,t2,t3 SET t1.f1='sample',t2.f1='sample',t3.f1='sample' WHERE t1.f1='test' and t2.f1='test' and t1.f1='test' [/CODE] using this,update fails if t2 and t3 could not find 'test' in their fields,if i use OR all records will be.. i have also tried JOINS [CODE] Update tbl_maincat AS m LEFT JOIN tbl_maincat AS m2 ON m.cTitle = m2.cTitle, tbl_main AS c LEFT JOIN tbl_main AS c2 ON c.MainCat = c2.Maincat, tbl_subcat AS s LEFT JOIN tbl_subcat AS s2 ON s.csCat = s2.csCat SET m.cTitle = 'Hardware25', m.cDesc = 'H2desc', c.MainCat = 'Hardware25', s.csCat = 'Hardware25' WHERE m.MainCatID=29 and c.Maincat='Hardware23' and s.csCat='Hardware23';[/CODE] same...because of the AND operator... if multiple query solved this..please let me know the proper construction in VB.net.. please everyone..its bugging me for almost a month.. im a newbie vb.net and mysql programmer.. thanks..