select id1,title1 from tab1 where title like '%key%' union select id2,title2 from tab2 where title2 like '%key%' union select id3,title3 from tab3 where title3 like '%key%'
select tab1.*,tab2.*,tab3.* from tab1,tab2,tab3 where tab1.title1="key" and tab2.title2="key" and tab3.title3="key";select tab1.*,tab2.*,tab3.* from tab1,tab2,tab3 where tab1.title1 like "%key%" and tab2.title2 like "%key%" and tab3.title3 like "%key%";
union select id2,title2 from tab2 where title2 like '%key%'
union select id3,title3 from tab3 where title3 like '%key%'
and tab2.title2="key" and tab3.title3="key";select tab1.*,tab2.*,tab3.* from tab1,tab2,tab3 where tab1.title1 like "%key%"
and tab2.title2 like "%key%" and tab3.title3 like "%key%";