Content Comparison

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1. In the project toolbar, click the leftmost Add button and click Data Source
2. Choose a connection name or click '+' to add a new one. This is optional, but makes it easy to find the connection parameters (the filename) next time.
3. In the Datasource field select Geospatial File
4. As Datatype select Vector Data or Raster, depending on the data type. Typical vector based file formats include ESRI shapefiles Esri Shapefiles or CSV. 
5. Select the file.
6. Click Connect. 

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A simple SELECT statement contains a single SELECT like "SELECT ....".

SELECT name, area from table1

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A UNION compound SELECT expression will append the table resulting from the second SELECT expression to the table resulting from the first SELECT. It looks like this:

SELECT name, area from table1 UNION SELECT name, area from table2

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A compound SELECT using INTERSECT will keep all rows that are present in both tables:

SELECT name,  area from table1 INTERSECT SELECT name, area from table2

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A compound expression using EXCEPT is conceptually similar to subtracting one table from another. For example, the following statement will subtract the rows of table2 from table1:

SELECT name,  area from table1 EXCEPT SELECT name, area from table2

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1. Open the SQL query editor
2. Click the SQL Wizard button and click Compare Tables. The welcome page of the table comparison will appear. Click Next.
3. Select the two tables that you wish to compare.
4. In the report page, select whether to compare attributes, geometry or features IDs (FID).
5. In the operation selector you can select which tables will constitute the operands of the comparison expression. Note that the EXCEPT operator is not symmetrical: table1 EXCEPT table2 is generally not the same as table2 EXCEPT table1.
6. Click Finish
7. Make any final modifications to the SQL statement in the SQL query editor
8. Click Execute. The result table will be listed in the editor.