SQL Loader-按组数据加载ID

Question

Hi I have a flat file which gets dumped into a table by using the sql loader. Lets say I have a records

col1 col2 col3  col4
263 Test1 data  1
263 Test2 data  1
264 Test3 data  2
264 test4 data  2

What I am trying to find out is there any way I can assign sequence number by grouping col1. If the col1 value is the same then all records should have the same value generated by a sequence. The function sequence(max,1) generates the next higher value, but how to group the col1 and then assign the same value to them. Thanks.

Answer 1

You seems want dense_rank() :

select *, dense_rank() over (order by col1) as seq
from table t;