Forum Discussion
Post ProdigyPower Query Structured lookup
There are some more examples that may confuse you. If you can understand them, then you understand "field access" (and projection) and the keyword each.
// Example 1 [A = 1, B = 2][[A], [C]]? // Example 2 #table({"A", "B"}, {{1, 2}, {1, 3}})[[D]]? // Example 3 let _ = [ A = 1, B = 2 ] in [A] // Example 4 let _ = [ A = 1, B = 2 ] in _[[A], [C]]?
Super UserThis is a native syntax that means find the only row in the table that meets the conditions.
You can find its usage in the Power Query documentation.
https://learn.microsoft.com/en-us/powerquery-m/m-spec-operators#selection-and-projection-operators
For example, tbl{[A=1, B=2]) means to find the row in table tbl where column A is equal to 1 and column B is equal to 2 (return a record value).
You may know that the operator ? can prevent errors when an item or field does not exist, but it may not work here. The operator ? can only avoid not being found. If multiple rows that meet the conditions are found, an error will still be returned.
// null
Table.FromValue({1, 2, 3, 3}){[Value = 4]}?
// error
Table.FromValue({1, 2, 3, 3}){[Value = 3]}?
Post ProdigyThanks I'll have a look,
I'll leave this open for a bit and see if anyone else has reading suggestions.
Richad.