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Google Fusion Tables: Merge Data

Merging Tables

You can merge data from different tables as long as they each have a column with matching and non-duplicating values.  This is comparable to the Merge command in Stata, the Join technique in ArcGIS, or the Join statement of SQL.

With a table open, click on the Merge link to initiate the merge process and follow the on-screen directions. Step-by-step instructions from Google.

Special points:

  • Values in the two columns on which you're performing the merge must exactly match.
  • These values must not duplicate in a column, to ensure a one-to-one relationship when performing the merge.
  • The resulting table will have the number of rows of Table A (the first table, or the left-hand table).
    • Any key values in the merge column of Table A that don't have a match in the merge column of Table B will result in a row with values in the Table-A-originating columns but no values in the Table-B-originating columns.
    • Rows in Table B with key values in the merge column that don't match any values in the merge column of Table A will be dropped in the result table.  To prevent these dropped rows, try merging tables in the opposite order.
  • Automatic updating: "If table C was created by merging tables A and B, then any update to A or B will be reflected in C. If you have edit permissions to a column in table C, then any edits you make will be reflected also in table A or B."
  • You can merge data into your data from a public table.
    • If you're looking at the public table, from that view you can merge your data into it to create a new merged table.
    • If you need to have your data table be "Table A" (see above), you first need to save the public table using File...Create View to list it among your own tables, so it will show up in the listing of tables you can merge with.
  • Choose File ... About to see which columns came from which source table.

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