sql server union if table exist
DECLARE @temp TABLE(empName varchar(100),empStoreNum varchar(100),empSales int,location varchar(20))
if object_id('table1') Is not null
insert into @temp
Select empName, empStoreNum, empSales, 'East' As SalesDistrict
FROM store1
if object_id('table2') is not null
insert into @temp
Select empName, empStoreNum, empSales, 'East' As SalesDistrict
FROM store2
if object_id('table3') is not null
insert into @temp
Select empName, empStoreNum, empSales, 'East' As SalesDistrict
FROM store3
select empName, empStoreNum, empSales,location
from @temp