oracle数据库合并来自多个表的结果

Question

I want to merge data coming from two tables :-

table T1 (id,c2,c3,switch)

table T2 (id,d2,d3 )

 T1 ----- id c1 c2 switch 1 joe darling Y 1 maria kk N T2 -------------- id d1 d2 1 sydney austraila 

now if the switch in T1 is 'Y'

i want the output as

 joe darling sydney australia // which is fine.. 

and if switch is 'N'

i still want the first and last name based on switch which is 'Y' and rest of the values from T2 table.

 joe darling sydney australia //how to achieve this. 

Answer 1

Suppose you've got only one Y switch per ID then try this:

SELECT 
     T12.C1, T12.C2, T2.d1, T2.D2
FROM T1
JOIN T1 as T12 ON (T1.ID=T12.ID) AND (T12.switch='Y')    
LEFT JOIN T2 on (T1.ID=T2.ID)

SQLFiddle demo