ST_Equalsrs checks to find if two spatial reference systems of two different feature classes are identical or not. If the spatial reference systems are identical, t (TRUE) is returned. If the spatial reference systems are not identical, ST_Equalsrs returns f (FALSE).

st_equalsrs (srid1 integer, srid2 integer)

Integer

In this example, the spatial reference IDs (SRID) of different feature classes are discovered, then ST_Equalsrs is used to see if the SRIDs represent the same spatial reference system or not.

SELECT srid, table_name
FROM sde_layers
WHERE table_name = 'transmains' OR table_name = 'streets';

srid	table_name
2	streets
6	transmains

Now, use ST_Equalsrs to determine if the spatial reference systems identified by these two SRIDs are the same.

SELECT st_equalsrs(2,6) ;

 st_equalsrs

-------------

          0

(1 row)