Help understanding Power BI error messages

Hi Sean and Greg_Deckler, thanks for your replies.

The steps in my query are in the screenshot. Unfortunately they are not labled in any useful terms. This was a learning project that ended up being used.

I've also attached the query from the query editor if that helps. 

let
    Source = Table.NestedJoin(#"bitnami_wordpress wp_esp_registration",{"EVT_ID"},#"bitnami_wordpress wp_posts",{"ID"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn" = Table.ExpandTableColumn(Source, "NewColumn", {"ID", "post_title", "post_type"}, {"NewColumn.ID", "NewColumn.post_title", "NewColumn.post_type"}),
    #"Merged Queries" = Table.NestedJoin(#"Expanded NewColumn",{"ATT_ID"},#"bitnami_wordpress wp_esp_attendee_meta",{"ATT_ID"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn1" = Table.ExpandTableColumn(#"Merged Queries", "NewColumn", {"ATT_ID", "ATT_fname", "ATT_lname", "ATT_city", "ATT_email"}, {"NewColumn.ATT_ID", "NewColumn.ATT_fname", "NewColumn.ATT_lname", "NewColumn.ATT_city", "NewColumn.ATT_email"}),
    #"Merged Queries1" = Table.NestedJoin(#"Expanded NewColumn1",{"EVT_ID"},#"bitnami_wordpress wp_esp_people_to_post",{"OBJ_ID"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn2" = Table.ExpandTableColumn(#"Merged Queries1", "NewColumn", {"PER_ID"}, {"NewColumn.PER_ID"}),
    #"Merged Queries2" = Table.NestedJoin(#"Expanded NewColumn2",{"EVT_ID"},#"bitnami_wordpress wp_esp_event_venue",{"EVT_ID"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn3" = Table.ExpandTableColumn(#"Merged Queries2", "NewColumn", {"VNU_ID"}, {"NewColumn.VNU_ID"}),
    #"Removed Duplicates" = Table.Distinct(#"Expanded NewColumn3"),
    #"Removed Columns" = Table.RemoveColumns(#"Removed Duplicates",{"REG_session", "REG_url_link", "REG_att_is_going", "REG_deleted"}),
    #"Renamed Columns" = Table.RenameColumns(#"Removed Columns",{{"NewColumn.ID", "Event ID"}, {"NewColumn.post_title", "Event Title"}, {"NewColumn.post_type", "Event.post_type"}, {"NewColumn.ATT_ID", "Attendee.ATT_ID"}, {"NewColumn.ATT_fname", "First Name"}, {"NewColumn.ATT_lname", "Last Name"}, {"NewColumn.ATT_city", "Attendee City"}, {"NewColumn.ATT_email", "Attendee Email"}, {"NewColumn.PER_ID", "Organiser"}, {"NewColumn.VNU_ID", "Venue ID"}}),
    #"Changed Type" = Table.TransformColumnTypes(#"Renamed Columns",{{"REG_date", type date}}),
    #"Filtered Rows" = Table.SelectRows(#"Changed Type", each ([Event ID] <> null) and ([Attendee.ATT_ID] <> null) and ([STS_ID] = "RAP")),
    #"Merged Queries3" = Table.NestedJoin(#"Filtered Rows",{"EVT_ID"},#"bitnami_wordpress wp_term_relationships",{"object_id"},"NewColumn",JoinKind.FullOuter),
    #"Expanded NewColumn4" = Table.ExpandTableColumn(#"Merged Queries3", "NewColumn", {"term_taxonomy_id"}, {"term_taxonomy_id"}),
    #"Merged Queries4" = Table.NestedJoin(#"Expanded NewColumn4",{"term_taxonomy_id"},#"bitnami_wordpress wp_terms",{"term_id"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn5" = Table.ExpandTableColumn(#"Merged Queries4", "NewColumn", {"name"}, {"name"}),
    #"Filtered Rows1" = Table.SelectRows(#"Expanded NewColumn5", each ([REG_ID] <> null)),
    #"Sorted Rows" = Table.Sort(#"Filtered Rows1",{{"REG_ID", Order.Ascending}}),
    #"Removed Duplicates1" = Table.Distinct(#"Sorted Rows", {"REG_ID"}),
    #"Merged Queries5" = Table.NestedJoin(#"Removed Duplicates1",{"TKT_ID"},#"bitnami_wordpress wp_esp_datetime_ticket",{"TKT_ID"},"NewColumn",JoinKind.LeftOuter),
    #"Removed Duplicates2" = Table.Distinct(#"Merged Queries5", {"REG_ID"}),
    #"Removed Columns1" = Table.RemoveColumns(#"Removed Duplicates2",{"NewColumn", "term_taxonomy_id", "name"})
in
    #"Removed Columns1"

I hope it formats properly, apologies if not. 

The registrations table itself is a merged query, linking the wordpress posts and event information from the events plugin. We've merged them as finding all the relationships individually was proving difficult. If we were to do this again we would probably take the time to find the relationships and link it together properly. However the queries were working after we had done this.

We pull through the WordPress posts table, an attendee meta table, and events table, events meta, venue, and venue meta. They all link back eventually to pull the correct data for each registration.

I'm inlclined to think you are on the right track Greg_Deckler as if there is an error, why no errors in the error report? and if it isn't an error then why does it say it is :S

Sean I have checked the source, the tables are the same as they were from day one and if i look in the table, the rows are there with the information. Is that what you meant?

The 'table is empty' message that i get is shown when i click the error logs themselves, if i go back to my registrations table the data is there.

But as i say though, the data is updating when i run the refresh. I have checked in the events system on the website itself, and also check the mySQL DB in sql Workbench. 

It's been bugging me for a little while now, but it has been managable. but i've got some time to sit and try and fix it now. 

I have attached a screenshot of all the tables i have in power BI desktop app. The ones with the blue underlines are merged tables which i can provide queries if needed. The ones labeled GA are all pulled from Google Analytics. The rest are WordPress tables, which i havent altered.

Thanks for your time guys, appreciate any help you can provide. 

Regards,

Phil