IF CONDITION

[#1]

Hi I have condition as below

(If Tag1<>’ ’, Tag1,Tag) as MapKey

The Above Condition would make data flow as below

SRNO	TAG	TAG1	MapKey
1	A		A
2	A	B	B
3	A	B	B
4	A	B	B
5	A		A

Still This Condition everything works fine but my database have even has value

As Below:

SRNO	TAG	TAG1	MapKey
1	A	B	B
2	A	B	B
3	A	B	B
4	A	B	B
5	A	B	B

Where all the MapKey are Replaced By TAG1 as per the Condition

(If Tag1<>’ ’, Tag1,Tag) as MapKey

Kindly suggest me condition to derive the below result

SRNO	TAG	TAG1	MapKey
1	A	B	B
2	A	B	B
3	A	B	B
4	A	B	B
5	A	B	B
6			A

Thanks In Advance

Vinayagam

[MK_QSL]

IF(TAG1='' and TAG='','A',IF(TAG1 <>'',TAG1,TAG)) as MapKey

[#3]

Thank you Sir

But i dont have any Tag1 or Tag has blank , i want to derive the result as the last table srno 6

[MK_QSL]

IF(TAG1='' and TAG='','A',IF(TAG1 <>'',TAG1,TAG)) as MapKey

Is not giving u desired result?  What I am missing?  Please explain