Need help to update the column value according other col

[Pacific007]

Exp.
Table name :School

col1 col2 col3
x a 1
y a 1
z a 1
x1 a 1
x2 a 2
x3 a 2
x4 a 2
x5 a 3

I need Output LIke this .Please help me.

col1 col2 col3
x a_1 1
y a_2 1
z a_3 1
x1 a_4 1
x2 a_1 2
x2 a_2 2
x3 a_3 2
x4 a_4 2
x5 a_1 3

[sonamasd@gmail.com]

Take 3 variables

v1 = if col3=v2 then v3+1 else 1

v2 = col3

v3 = v1

and then in derivation of col2 give col2 : '_' : v1

I thnk it should work for ur requirement

[zulfi123786]

Take 3 variables

v1 = if col3=v2 then v3+1 else 1

v2 = col3

v3 = v1

and then in derivation of col2 give col2 : '_' : v1

Unnecesay variale V3:

Reframe as:

v1 = if col3=v2 then v1+1 else 1

v2 = col3

[sonamasd@gmail.com]

I think no need to take 3rd variable

below should work

v1 = if col3=v2 then v1+1 else 1

v2 = col3

and then in derivation of col2 give col2 : '_' : v1

[Pacific007]

Take 3 variables

v1 = if col3=v2 then v3+1 else 1

v2 = col3

v3 = v1

and then in derivation of col2 give col2 : '_' : v1

I thnk it should work for ur requirement

Thanks Dear..This is working fine