Logic is very important: a statement of SQL, but I think for a long while, around a big bend

Problem: After the system upgrade audit authentication information to write two tables, now need to link the user table and the corresponding new and old audit table to get the field values?

Into the alley: has been tangled in the upgrade after the member information from the new table, the data before the upgrade from the old table, tangled in the time-stamp according to the conditions of judgment,

　　　　　　　　In fact, as long as the new and old two audit tables merged into a table can be, directly from the newly generated table inside query can!

SELECT ! ISNULL (Ia.approve_stat) ispost,from_unixtime (ia.first_approve_time, '%y-%m-%d%h:%i:%s ') first_approve_time
from Edo_user U-leftJOIN ((SELECT * from Edo_cp_identity_approve) UNION (SELECT * from Edo_cp_identi ty_approve_new)) as ia on
U.uid = ia.user_id

Half an hour to solve the problem, oneself and spend a day, it seems that the logic of thinking is how important

Logic is very important: a statement of SQL, but I think for a long while, around a big bend