Syntax
Table.AddJoinColumn(table1 as table, key1 as any, table2 as function, key2 as any, newColumnName as text) as table
Description
Joins the rows of table1 with the rows of table2 based on the equality of the values of the key columns selected by key1 (for table1) and key2 (for table2). The results are entered into the column named newColumnName. This function behaves similarly to Table.Join with a JoinKind of LeftOuter except that the join results are presented in a nested rather than flattened fashion.
Reference Data
https://docs.microsoft.com/en-us/powerquery-m/power-query-m-function-reference