[postgis-users] whats the different between ST_Extent() and ST_Estimated_Extent()

[nguyen liem]

Hi All,

I have 2 queries:
SELECT ST_Extent(point) FROM schema.mytable;
SELECT ST_Estimated_Extent('schema', 'mytable', 'point');

2 queries above were returned for me *same result* (BOX2D):
"BOX(11.1806726455688 55.3748893737793,24.1317653656006 67.8551025390625)"
I don't know what is the different between 2 functions, should I use  *
ST_Extent* or *ST_Estimated_Extent* in this case.
And ... Will be better, if you explain me when we need to use
*ST_Extent*and when we need to use
*ST_Estimated_Extent*  ;)

Cheers.

-- 
Liem Nguyen
Developer
Axon Active Corp.
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