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How to run SQL query in QGIS?
This will involve running an SQL query, then saving it with QGIS.
- In QGIS, connect to the database with the seattlecrimes dataset (if not already done).
- In QGIS, click (in menu) Database > DB manager, select the dssg2016 database, and open the SQL Window using File > SQL Window, clicking its icon, or hitting ‘F2’.
Does Qgis use SQL?
Supported language. The underlying engine uses SQLite and Spatialite to operate. It means you can use all of the SQL your local installation of SQLite understands. Functions of QGIS expressions can also be used in a virtual layer query.
What is a query in Qgis?
The Query Builder allows you to define a subset of a table using a SQL-like WHERE clause and to display the result in the main window. The query result can then be saved as a new vector layer.
How to use the DB Manager interface in QGIS?
You have now seen how to use the DB Manager interface in QGIS to Manage your spatial databases, to execute sql queries against your data and how to import and export data. 18.2.8. What’s Next? ¶
How to create a SQL-like query in QGIS?
The Fields, Values and Operators sections help you to construct the SQL-like query. The Fields list contains all attribute columns of the attribute table to be searched. To add an attribute column to the SQL WHERE clause field, double click its name in the Fields list.
Where are the last 20 queries stored in QGIS?
The Query History button stores the last 20 queries of each database and provider. Double clicking on an entry will add the string to the SQL window. The SQL Window can also be used to create Virtual Layers. In that case, instead of selecting a database, select QGIS Layers under Virtual Layers before opening the SQL Window.
How to list the values of an attribute in QGIS?
To list all possible values of an attribute, select the attribute in the Fields list and click the [all] button. To list the first 25 unique values of an attribute column, select the attribute column in the Fields list and click the [Sample] button. To add a value to the SQL WHERE clause field, double click its name in the Values list.