Forum Discussion
Merge queries. How replace a row?
If my understanding of the problem is correct, this would probably be the easiest option:
1) Append the long table to your table that holds the replacements
2) Check the index column and remove duplicates
Removing duplicates will keep the first row it finds in a table. This should also be fast.
stretcharm Thanks. Yes that would work, but I could potentially have a few hundred random rows I would like to replace and I would like to find a more automated solution where the rows in one table could simple replace the rows in the other table and use the index column as the common column to identify which rows to replace.
You can use a Left Anti to get a data set from the first list that doesnt have rows in the 2nd then append the 2nd.
You could also create a function to replace values, but I suspect this will be very slow on a large dataset.
https://msdn.microsoft.com/en-us/query-bi/m/table-replacevalue
This is a useful blog from cwebb that uses Table.AddKey to improve merge performance.
https://blog.crossjoin.co.uk/2018/03/16/improving-the-performance-of-aggregation-after-a-merge-in-power-bi-and-excel-power-query-gettransform/
https://msdn.microsoft.com/query-bi/m/table-addkey
If my understanding of the problem is correct, this would probably be the easiest option:
1) Append the long table to your table that holds the replacements
2) Check the index column and remove duplicates
Removing duplicates will keep the first row it finds in a table. This should also be fast.