Contenu <\/p>\nToggle<\/span>

A Simple but Valuable Addition<\/a><\/li>
Simple Example: Select Parcels Over One Hectare<\/a><\/li>
Spatial Example: Parcels Within 200 m of Rivers<\/a><\/li>
Practical Tips<\/a><\/li>
A Great Time-Saver for Advanced Users<\/a><\/li>
In Summary<\/a><\/li><\/ul><\/nav><\/div>\n
<\/span> A Simple but Valuable Addition<\/span><\/h3>\n\n\n\n
Right-clicking on a vector layer (whether from a database or a local file like a GeoPackage<\/a>) now shows a new entry: SQL Query\u2026<\/strong><\/p>\n\n\n\n
$\"\"$ <\/a><\/figure>\n\n\n\n
This command opens a lightweight SQL editor window where you can:<\/p>\n\n\n\n
\n
Filter features<\/strong> by attributes or geometry,<\/li>\n\n\n\n
Generate new geometries<\/strong> (buffer, intersection, etc.),<\/li>\n\n\n\n
Perform aggregations<\/strong> (sum, count, average, etc.).<\/li>\n<\/ul>\n\n\n\n\n
The functionality is powered by QGIS SQL<\/strong>, a flexible engine that works with both local datasets and remote spatial databases (e.g., PostGIS<\/a>).<\/p>\n\n\n\n
The result of the query is displayed in a dedicated window as a list of records matching the specified criteria. You can review the results directly, but more importantly, by using the \u201cLoad as new layer\u201d<\/strong> option, the query result can be added as a virtual layer<\/strong> in the Layers<\/em> panel. This allows you to reuse the filtered dataset instantly, without duplicating data, and with the flexibility of dynamic access to your selection.<\/p>\n\n\n\n
This layer is temporary <\/strong>and not saved by default. If you wish to keep it or use it in another project, you can then save it manually<\/strong> in a format of your choice (GeoPackage, Shapefile<\/a>, etc.) by right-clicking > \u201cExport\u201d.<\/p>\n<\/blockquote>\n\n\n\n
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<\/span>Simple Example: Select Parcels Over One Hectare<\/span><\/h3>\n\n\n\n
Here’s a basic query that selects only the parcels larger than 10,000 m\u00b2 (1 hectare):<\/p>\n\n\n\n
SELECT *\nFROM cadastre_rodrigues\nWHERE ST_Area(geometry) > 10000\n<\/code><\/pre>\n\n\n\nThis returns a subset of the features, directly viewable and usable in your map project.<\/p>\n\n\n\n \n\n\n\n<\/span>Spatial Example: Parcels Within 200 m of Rivers<\/span><\/h3>\n\n\n\nIf you have a rivieres_rodrigues<\/code> layer loaded, you can find intersections with a 200 m buffer around the rivers:<\/p>\n\n\n\nSELECT \n p.id,\n ST_Intersection(p.geometry, ST_Union(ST_Buffer(r.geometry, 200))) AS geometry\nFROM cadastre_rodrigues AS p,\n rivieres_rodrigues AS r\nWHERE ST_Intersects(p.geometry, ST_Buffer(r.geometry, 200))\n<\/code><\/pre>\n\n\n\nThis query returns the actual intersected geometries<\/strong>, not the entire parcel.<\/p>\n\n\n\n<\/a><\/figure>\n\n\n\n \n\n\n\n<\/span>Practical Tips<\/span><\/h3>\n\n\n\n\nYou must include a geometry<\/code> column in your result for it to be displayed on the map.<\/li>\n\n\n\n The SQL engine supports a wide range of spatial functions (ST_Buffer<\/code>, ST_Intersection<\/code>, ST_Union<\/code>, ST_Area<\/code>, etc.).<\/li>\n\n\n\n Query results can be added to the project<\/strong>, saved as virtual layers<\/strong>, or exported to a new file<\/strong> (e.g., GeoPackage).<\/li>\n<\/ul>\n\n\n\n \n\n\n\n<\/span> A Great Time-Saver for Advanced Users<\/span><\/h3>\n\n\n\nPreviously, running SQL queries required opening:<\/p>\n\n\n\n \nThe DB Manager<\/strong> (for database layers),<\/li>\n\n\n\n The Virtual Layer<\/strong> interface (for local file-based layers),<\/li>\n\n\n\n Or the Processing Toolbox<\/strong> for spatial queries.<\/li>\n<\/ul>\n\n\n\nThe new context menu command \u201cSQL Query\u2026\u201d<\/strong> streamlines this process and encourages experimentation and productivity.<\/p>\n\n\n\n \n\n\n\n<\/span> In Summary<\/span><\/h3>\n\n\n\nThis new option in the context menu is a welcome addition to QGIS<\/strong>. It bridges the gap between powerful SQL capabilities and everyday GIS workflows.<\/p>\n\n\n\n By enabling direct access to SQL on any layer, QGIS empowers users to explore, transform, and filter data more efficiently<\/strong>, without needing to write full scripts or run multiple tools.<\/p>\n\n\n\n \n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":" Starting with QGIS version 3.42, a subtle but powerful feature has been added to the context menu of vector layers: the \u201cSQL Query\u2026\u201d option. This improvement provides a direct and user-friendly interface for running SQL queries,…<\/p>\n","protected":false},"author":1,"featured_media":14178,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"sfsi_plus_gutenberg_text_before_share":"","sfsi_plus_gutenberg_show_text_before_share":"","sfsi_plus_gutenberg_icon_type":"","sfsi_plus_gutenberg_icon_alignemt":"","sfsi_plus_gutenburg_max_per_row":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[1377],"tags":[3001,3298,1386,1353],"class_list":["post-14177","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-qgis-en","tag-layers","tag-menu-en","tag-qgis-en","tag-sql-en"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t