How can I combine rows based on two columns matching in KQL?

Question

I am trying to get a number of rows combined within a table in a KQL log analytics query. My current query result, or input table, is this:

id	name	InstanceId	MonthlyPreTaxCost
		vm-for-oe-ip	0.247
		vmtest-ip	0.263
test-orphaned-ip	test-orphaned-ip
vmTest-ip	vmTest-ip

What I want, is a result that contains only a single record: vmTest-ip as the id, the name, and then the MonthlyPreTaxCost associated with that id:

id	name	InstanceId	MonthlyPreTaxCost
vmTest-ip	vmTest-ip	vmtest-ip	0.263

I initially thought I should do this using a self join, but I cannot get the condition check (id == InstanceId) right. Inner joining on itself, for example, gives this:

id	name	InstanceId	MonthlyPreTaxCost	id1	name1	InstanceId1	MonthlyPreTaxCost1
		vmtest-ip	0.263	test-orphaned-ip	test-orphaned-ip
		vm-for-oe-ip	0.247	test-orphaned-ip	test-orphaned-ip
		vmtest-ip	0.263	vmTest-ip	vmTest-ip
		vm-for-oe-ip	0.247	vmTest-ip	vmTest-ip

How can I achieve my desired result?

Answer 1

The solution turned out to be quite simple: change the condition check to be non-case sensitive (=~ instead of ==). This fixed my problem.