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Introduction
ST_Equals
Relationships Between Geometries
ST_Distance and ST_Dwithin
Spatial joins practice
Summary
23. Summary

## Instruction

Well done! You've come a long way. It's time to wrap things up.

In this part of the course, we learned how to compare geometries with one another. We learned about the following useful functions:

• ST_Equals(geomA,geomB) checks if two geometries have the same coordinates.
• ST_Overlaps(geomA,geomB) checks if two objects have some (but not all) space in common.
• ST_Touches(geomA,geomB) checks if two objects touch at a common border (but don't overlap).
• ST_Within(geomA,geomB) checks if geomA is entirely contained within geomB.
• ST_Contains(geomA, geomB) - checks if geomB is entirely contained within geomA.
• ST_Intersects(geomA,geomB) - checks whether two objects have any space or borders in common.
• ST_Distance(geomA,geomB) returns the shortest distance between two geometries.
• ST_DWithin(geomA,geomB,distanceX) checks whether geomA and geomB are within distance X of each other.
• Spatial joins use spatial functions in the ON clause. Most of the time, these are ST_Intersects or ST_Contains.
• You can also add further elements to spatial joins, such as aggregate functions with GROUP BY clauses.
• You can also use a spatial function like ST_Length inside an aggregate function.

Alright, it's now time to practice all you've learned!

## Exercise

Click to start the quiz.