How do i get a bounding polygon around points?

I have a table with thousands of addresses开发者_JAVA技巧 as points.

Is there a function in postgis that will allow me to get a bounding polygon around these points and return it as a polygon?

update I am looking for a more complex polygon than just a bounding rectangle

It may be not 100% clear from your question what you mean as more bounding polygon. It may be understood as

• minimum bounding rectangle (also known as MBR or envelope) for which you can use ST_Envelope, ST_Box2D or ST_Extent,

• as s a minimum geometry which encloses all points within given geometry, a convex envelope and in this case you can use ST_ConvexHull or even ST_ExteriorRing if your input would be a polygon,

• As Pimin pointed in the comments below, ST_ConcaveHull is another option worth to consider, available since PostGIS 2.0.0.

ST_Extent provides an aggregate function that returns a bounding box that bounds a set of geometries.