SELECT t.servic_id, t.service_date
FROM (
    SELECT field1, field2, Field3
    FROM tbl_add_service_installation 
    UNION ALL 
    SELECT field1, field2, field3 FROM table2
) as t
WHERE t.field3=1

 SELECT tasi.service_id as serviceid, tasi.client_name as clientname,tasi.mobile_no as mobileno,product as productname
tsid.service_date as srevicedate
    FROM tbl_add_service_installation as  tasi
 inner join  tbl_service_installation_details as tsid on tsid.servic_id=tasi.service_id



select  service_id as serviceid,client_name as clientname,mobile_no as mobileno,
product_service as productname,service_date as srevicedate
  from Complaint_On_Demand_Services



SELECT a.serviceid,a.clientname ,a.mobileno,a.productname,a.srevicedate  FROM (
 SELECT tasi.service_id as serviceid, tasi.client_name as clientname,tasi.mobile_no as mobileno,product as productname
tsid.service_date as srevicedate
    FROM tbl_add_service_installation as  tasi
 inner join  tbl_service_installation_details as tsid on tsid.servic_id=tasi.service_id

 UNION ALL 

select  service_id as serviceid,client_name as clientname,mobile_no as mobileno,
product_service as productname,service_date as srevicedate
  from Complaint_On_Demand_Services
) as a