Optimising The Performance Of Power Query Merges In Power BI, Part 3: Table.Join And SortMerge

When you merge data from two queries in the Power Query Editor the M code generated uses the Table.NestedJoin function. There is, however, another M function that can be used to merge data: Table.Join. The interesting thing about this function is that has a parameter that Table.NestedJoin doesn’t have: the joinAlgorithm parameter allows you to specify the algorithm used by the Power Query engine for the merge.

Source : Chris Webb’s BI Blog
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