mysql - sql query with case/COALESCE statement -

i have query working perfectly.but there situation have join 2 query in case statement.but problem 1 of query in use.so question how add 2 sql in 1 sql

my original sql

select tc.dentist_id,md.vendor_no,pl.pack_trans_id,tc.agent_dentist,md.company_name,md.contact,md.phone_no,sql1.image_path,sql1.metal_id,sql1.expect_more,sql1.how_long_acquire,tc.check_amt,tc.check_date_sent,tc.check_no           tbl_check tc           left join tbl_mst_dentist md on tc.dentist_id=md.dentist_id           left join tbl_pack_list pl   on tc.pack_id=pl.pack_id            left join (select image_path,pack_id,metal_id,expect_more,how_long_acquire tbl_metals_list  group  pack_id           )sql1 on tc.pack_id=sql1.pack_id           tc.sale_agent_id = '3' , tc.paying_percent !=0  

now have add 2 sql statement in above statement

if(tc.agent_dentist=a) select sa.* ,sm.state_code tbl_sales_agent sa,tbl_mst_state sm sa.sales_agent_id = '3' , sa.state=sm.state_name else select * tbl_mst_dentist dentist_id =tc.dentist_id 

second table in use.is possible? in advance

yes, can use alias different name. e.g. table any_alias.

select * t1 join t2 alias_a on (alias_a.t1_id = t1.id) join t2 alias_b on (alias_b.t1_id = t1.id)