Multiple conditions in aggregations

In Power Query M language, you can use the "and" or "or" conditions to combine multiple conditions. However, it looks like you have a small syntax error in your code. You should use the "and" operator within the Table.SelectRows function. Here's the revised code with both conditions:

{"Repair Date", each [Repair Date]{0}, type date},
{"Insured Date", each [Insured Date]{0}, type date},
{"avg 3 repairs cost before", (t)=>
List.Average(
List.LastN(
Table.SelectRows(t, each [Failure Date] < [Repair Date] and [Failure Date] < [Insured Date])[Repair Cost],
3
)
), type number
}

In the revised code, I've used the "and" operator to ensure that both conditions [Failure Date] < [Repair Date] and [Failure Date] < [Insured Date] are met when filtering the rows using Table.SelectRows. This should calculate the average of "Repair Cost" for rows that satisfy both conditions.

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