Problem with merge, "Value was not specified" error

[kalleeljas]

Hello.

Im trying to merge two tables to create a uniqe ID from customernumber and product.

The table "ANLÄGGNINGAR" contain the ID i want to use (column "Cistern").

The example below is a successful merge (i get the ID from "ANLÄGGNINGAR" into "Garplev") that i would like to do on another table:

In the example below im trying to merge "Sitevision" and "ANLÄGGNINGAR" but i cant even see the 2nd table with the error message "Value was not specified"

Note that i can merge from "sitevision" to "ANLÄGGNINGAR" but not the other way around. The problem is that i dont understand what "Value was not specified" means.

[Multa]

Hello! Thanks to the author for the solution: it helped. In my case the reason was in a ciclic connections between the queries, ha-ha.

[Anonymous]

I ended up here on a DuckDuckGo search for th same error. I was getting the same error and was able to get around it with the merge as new, but that wasn't a solution.

I had a look at mine again and noticed that I was creating a circular reference even though I wasn't getting the circular reference error. I had the main query and referenced this main query to do some cleaning and then tried to merge this new query back into the main query! (Stupid I know). I stripped the main into 2 queries (raw data + cleaning queries) and the third query to do other matching etc. Query 2 and 3 referened Query 1 and works fine. 

Query 2 reference Query 1 > Query 1 merge Query 2 = "Value was not specified"

Query 2 and 3 reference Query 1 (raw data) > Query 2 merge Query 3 = OK

[kalleeljas]

I made a workaround to solve the problem, I tried again recently with an updated version of PBI desktop and It worked.

[v-micsh-msft · Accepted solution]

Hi kalleeljas,

Could you please share us some simple data about the "Sitevision" and "ANLÄGGNINGAR" tables?

I created some simple table to test and can’t reproduce the error, this should not be related with the join option selected. Please check the table information first, which I suspect the key point should be the "ANLÄGGNINGAR" table.

In addition, check your Power BI desktop version, make sure it is up-to-date.

The latest version is available in the following link:

https://powerbi.microsoft.com/en-us/desktop/

Regards

[Anonymous]

I worked around this error by "Merging Queries as New" instead of just a merge. It's not really a solution but it allowed me to get around the join problem!

[BhaveshPatel]

Hi there,

The reason behind this is that The LEFT JOIN returns all rows from the left table (table1), with the matching rows in the right table (table2). The result is NULL in the right side when there is no match and PowerQuery smart sense doesn't even let you create that join if the condition for that is not met.

Hope this has clarified your understanding of left join.