Is important Repeat yourself rule for CQRS

I wonder using design principle rule that named DRY(Do not repeat yourself) on CQRS.

I have 2 type of Geometric table named WaterPipes, GasPipes.

public GasPipe{ id, Name, Length, .... }
public WaterPipe{ id, Name, Length .... }

So I am new at using CQRS. I want to create a query to get total length of them.

Database query will be similar.

Select Sum(Length) From GasPipes, 
Select Sum(Length) From WaterPipes

So now can I create one Query?

public class PipeLengthQuery { }
public class PipeLengthQueryHandler {
    if(water) Select Sum(Length) From WaterPipes
    if(gaz) Select Sum(Length) From GasPipes
}

Or separate query types:

public class WaterPipeLengthQuery { }
public class GasPipeLengthQuery { }
public class GasPipeLengthQueryHandler { }
public class WaterPipeLengthQueryHandler { }

Which of it best?