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I have two shapefiles: One point file (occ_master) and 1 polygon file (geol_1m). The point file represents mineral occurrences. The polygon file represents geology, which can be subcategorized by field lith_name, as displayed in the image. I need to find a way to determine how many mineral occurrences (points) occur in each lith_name. This query will allow me to figure out which geological unit has the most mineral occurrences.

I know it will involve a ST_Contains and GROUP BY query but it is my first day on PostGIS and so I am rather inexperienced.

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    So, do you have shapefiles (file-based geodata format from last century) or database tables (in PostgreSQL using PostGIS geometry)? When loaded into the database, shapefiles become "tables" not "files". If you have tables, we ask that you make an attempt at the SQL (note that ST_Contains will not handle boundary conditions, so you might get a lower total than the actual number of points). – Vince Feb 19 at 14:24
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