ST_ConvexHull() method

Syntax

geometry-expression.ST_ConvexHull()

ST_Geometry If the geometry value is NULL or an empty value, then NULL is returned. Otherwise, the convex hull of the geometry value is returned.

Example 1 – The following example shows the convex hull computed from 10 points. The resulting hull is the result Polygon ((1 1, 7 2, 9 3, 6 9, 4 9, 1 5, 1 1)). Convex hull of a set of points
```
SELECT NEW ST_MultiPoint('MultiPoint( (1 1), (2 2), (5 3), (7 2), (9 3), (8 4), (6 6), (6 9), (4 9), (1 5) )').ST_ConvexHull()
```
The following example returns the single point (0,0). The convex hull of a single point is a point.
```
SELECT NEW ST_Point(0,0).ST_ConvexHull()
```
The following example returns the result LineString (0 0, 3 3). The convex hull of a single straight line is a linestring with a single segment.
```
SELECT NEW ST_LineString('LineString(0 0,1 1,2 2,3 3)').ST_ConvexHull()
```

SQL/MM (ISO/IEC 13249-3: 2006) 5.1.16