Tip
ST_ISVALID
to determine if a geometry object is valid. The
functions below work best with valid geometry objects.REMOVE_NULLABLE
function to
remove any nullable
column types that could result from calculating a
derived column (e.g., as in Projections) using one of the
functions below.The functions below all compare x
and y
coordinates to geometry objects
(or vice versa), thus increasing their performance in queries. Each of these
functions have a geometrytogeometry version listed in the next section.
Function  Description 

STXY_CONTAINS(geom, x, y) 
Returns 1 (true) if geom contains the x and y coordinate, e.g. lies in the interior
of geom . The coordinate cannot be on the boundary and also be contained because geom does not
contain its boundary 
STXY_CONTAINSPROPERLY(geom, x, y) 
Returns 1 (true) if the x and y coordinate intersects the interior of geom but not
the boundary (or exterior) because geom does not contain its boundary but does contain itself 
STXY_COVEREDBY(x, y, geom) 
Returns 1 (true) if the x and y coordinate is covered by geom 
STXY_COVERS(geom, x, y) 
Returns 1 (true) if geom covers the x and y coordinate 
STXY_DISJOINT(x, y, geom) 
Returns 1 (true) if the given x and y coordinate and the geometry geom do not
spatially intersect. 
STXY_DISTANCE(x, y, geom[, solution]) 
Calculates the minimum distance between the given
Note: If the 
STXY_DWITHIN(x, y, geom, distance[, solution]) 
Returns

STXY_ENVDWITHIN(x, y, geom, distance[, solution]) 
Returns

STXY_ENVINTERSECTS(x, y, geom) 
Returns 1 (true) if the bounding box of the given geometry geom intersects the x and
y coordinate. 
STXY_INTERSECTION(x, y, geom) 
Returns the shared portion between the x and y coordinate and the given geometry geom ,
i.e. the point itself. 
STXY_INTERSECTS(x, y, geom) 
Returns 1 (true) if the x and y coordinate and geom intersect in 2D. 
STXY_TOUCHES(x, y, geom) 
Returns 1 (true) if the x and y coordinate and geometry geom have at least one point
in common but their interiors do not intersect. If geom is a GEOMETRYCOLLECTION, a 0 is
returned regardless if the point and geometry touch 
STXY_WITHIN(x, y, geom) 
Returns 1 (true) if the x and y coordinate is completely inside the geom geometry
i.e., not on the boundary 
Function  Description 

DIST(x1, y1, x2, y2) 
Computes the Euclidean distance (in degrees), i.e. SQRT( (x1x2)*(x1x2) + (y1y2)*(y1y2) ) . 
GEODIST(lon1, lat1, lon2, lat2) 
Computes the geographic greatcircle distance (in meters) between two lat/lon points. 
GEOHASH_DECODE_LATITUDE(geohash) 
Decodes a given geohash and returns the latitude value for the given hash string. Supports a
maximum geohash character length of 16. 
GEOHASH_DECODE_LONGITUDE(geohash) 
Decodes a given geohash and returns the longitude value for the given hash string. Supports a
maximum geohash character length of 16. 
GEOHASH_ENCODE(lat, lon, precision) 
Encodes a given coordinate pair and returns a hash string with a given precision . 
ST_ADDPOINT(linestring, point, position) 
Adds a the given point geometry to the given linestring geometry at the specified
position , which is a 0based index. 
ST_ALMOSTEQUALS(geom1, geom2, decimal) 
Returns 1 (true) if given geometries, geom1 and geom2 , are almost spatially equal within
the given amount of decimal scale. Note that geometries will still be considered equal if the
decimal scale for the geometries is within a half order of magnitude of each other, e.g, if
decimal is set to 2, then POINT(63.4 123.45) and POINT(63.4 123.454) are equal, but
POINT(63.4 123.45) and POINT(63.4 123.459) are not equal. The geometry types must match to be
considered equal. 
ST_AREA(geom[, solution]) 
Returns the area of the given geometry

ST_AZIMUTH(geom1, geom2) 
Returns the azimuth in radians defined by the segment between two POINTs, geom1 and geom2 .
Returns a null if the input geometry type is MULTIPOINT, (MULTI)LINESTRING, or (MULTI)POLYGON. 
ST_BOUNDARY(geom) 
Returns the closure of the combinatorial boundary of a given geometry geom . Returns an empty
geometry if geom is an empty geometry. Returns a null if geom is a GEOMETRYCOLLECTION 
ST_BOUNDINGDIAGONAL(geom) 
Returns the diagonal of the given geometry's (geom ) bounding box. 
ST_BUFFER(geom, radius[, style[, solution]]) 
Returns a geometry that represents all points whose distance from the given geometry Available
Available
Tip To create a 5meter buffer around 
ST_CENTROID(geom) 
Calculates the center of the given geometry geom as a POINT. For (MULTI)POINTs, the center is
calculated as the average of the input coordinates. For (MULTI)LINESTRINGs, the center is calculated
as the weighted length of each given LINESTRING. For (MULTI)POLYGONs, the center is calculated as
the weighted area of each given POLYGON. If geom is an empty geometry, an empty
GEOMETRYCOLLECTION is returned 
ST_CLIP(geom1, geom2) 
Returns the geometry shared between given geometries geom1 and geom2 
ST_CLOSESTPOINT(geom1, geom2[, solution]) 
Calculates the 2D

ST_COLLECT(geom1, geom2) 
Returns a MULTI* or GEOMETRYCOLLECTION comprising geom1 and geom2 . If geom1 and geom2
are the same, singular geometry type, a MULTI* is returned, e.g., if geom1 and geom2 are both
POINTs (empty or no), a MULTIPOINT is returned. If geom1 and geom2 are neither the same type
nor singular geometries, a GEOMETRYCOLLECTION is returned. 
ST_COLLECTIONEXTRACT(collection, type) 
Returns only the specified

ST_COLLECTIONHOMOGENIZE(collection) 
Returns the simplest form of the given collection , e.g., a collection with a single POINT will
be returned as POINT(x y) , and a collection with multiple individual points will be returned as a
MULTIPOINT. 
ST_CONCAVEHULL(geom, target_percent[, allow_holes]) 
Returns a potentially concave geometry that encloses all geometries found in the given geom set.
Use target_percent (values between 0 and 1) to determine the percent of area of a convex hull the
concave hull will attempt to fill; 1 will return the same geometry as an ST_CONVEXHULL
operation. Set allow_holes to 1 (true) to allow holes in the resulting geometry; default
value is 0 (false). Note that allow_holes is independent of the area of target_percent . 
ST_CONTAINS(geom1, geom2) 
Returns 1 (true) if no points of geom2 lie in the exterior of geom1 and at least one
point of geom2 lies in the interior of geom1 . Note that geom1 does not contain its
boundary but does contain itself. 
ST_CONTAINSPROPERLY(geom1, geom2) 
Returns 1 (true) if geom2 intersects the interior of geom1 but not the boundary
(or exterior). Note that geom1 does not contain its boundary but does contain itself. 
ST_CONVEXHULL(geom) 
Returns the minimum convex geometry that encloses all geometries in the given geom set. 
ST_COORDDIM(geom) 
Returns the coordinate dimension of the given geom , e.g., a geometry with x , y , and z
coordinates would return 3 . 
ST_COVEREDBY(geom1, geom2) 
Returns 1 (true) if no point in geom1 is outside geom2 . 
ST_COVERS(geom1, geom2) 
Returns 1 (true) if no point in geom2 is outside geom1 . 
ST_CROSSES(geom1, geom2) 
Returns 1 (true) if the given geometries, geom1 and geom2 , spatially cross, meaning some
but not all interior points in common. If geom1 and/or geom2 are a GEOMETRYCOLLECTION, a
0 is returned regardless if the two geometries cross 
ST_DIFFERENCE(geom1, geom2) 
Returns a geometry that represents the part of geom1 that does not intersect with geom2 . 
ST_DIMENSION(geom) 
Returns the dimension of the given geometry geom , which is less than or equal to the coordinate
dimension. If geom is a single geometry, a 0 is for POINT , a 1 is for LINESTRING ,
and a 2 is for POLYGON . If geom is a collection, it will return the largest dimension from
the collection. If geom is empty, 0 is returned. 
ST_DISJOINT(geom1, geom2) 
Returns 1 (true) if the given geometries, geom1 and geom2 , do not spatially intersect. 
ST_DISTANCE(geom1, geom2[, solution]) 
Calculates the minimum distance between the given geometries,
Note: If 
ST_DISTANCEPOINTS(x1, y1, x2, y2[, solution]) 
Calculates the minimum distance between the given points,

ST_DFULLYWITHIN(geom1, geom2, distance[, solution]) 
Returns

ST_DWITHIN(geom1, geom2, distance[, solution]) 
Returns

ST_ELLIPSE(centerx, centery, height, width) 
Returns an ellipse using the following values:

ST_ENDPOINT(geom) 
Returns the last point of the given geom as a POINT if it's a LINESTRING. If geom is not a
a LINESTRING, null is returned. 
ST_ENVDWITHIN(geom1, geom2, distance[, solution]) 
Returns

ST_ENVELOPE(geom) 
Returns the bounding box of a given geometry geom . 
ST_ENVINTERSECTS(geom1, geom2) 
Returns 1 (true) if the bounding box of the given geometries, geom1 and geom2 , intersect. 
ST_EQUALS(geom1, geom2) 
Returns 1 (true) if the given geometries, geom1 and geom2 , are spatially equal. Note that
order does not matter. 
ST_EQUALSEXACT(geom1, geom2, tolerance) 
Returns 1 (true) if the given geometries, geom1 and geom2 , are almost spatially equal
within some given tolerance . If the values within the given geometries are within the
tolerance value of each other, they're considered equal, e.g., if tolerance is 2,
POINT(1 1) and POINT(1 3) are considered equal, but POINT(1 1) and POINT(1 3.1) are not. Note that
the geometry types have to match for them to be considered equal. 
ST_ERASE(geom1, geom2) 
Returns the result of erasing a portion of geom1 equal to the size of geom2 . 
ST_EXPAND(geom, units) 
Returns the bounding box expanded in all directions by the given units of the given geom . The
expansion can also be defined for separate directions by providing separate parameters for each
direction, e.g., ST_EXPAND(geom, unitsx, unitsy, unitsz, unitsm) . 
ST_EXPANDBYRATE(geom, rate) 
Returns the bounding box expanded by a given rate (a ratio of width and height) for the given
geometry geom . The rate must be between 0 and 1. 
ST_EXTERIORRING(geom) 
Returns a LINESTRING representing the exterior ring of the given POLYGON geom 
ST_GENERATEPOINTS(geom, num) 
Creates a MULTIPOINT containing a number num of randomly generated points within the boundary of
geom . 
ST_GEOHASH(geom, precision) 
Returns a hash string representation of the given geometry Note The value returned will not be a geohash of the exact geometry but a geohash of the centroid of the given geometry 
ST_GEOMETRYN(geom, index) 
Returns the index geometry back from the given geom geometry. The index starts from 1 to
the number of geometry in geom . 
ST_GEOMETRYTYPE(geom) 
Returns the type of geometry from the given geom . 
ST_GEOMETRYTYPEID(geom) 
Returns the type ID of from

ST_GEOMFROMGEOHASH(geohash, precision) 
Returns a POLYGON boundary box using the given geohash with a precision set by the integer
precision . If precision is specified, the function will use as many characters in the hash
equal to precision to create the geometry. If no precision is specified, the full length of
the geohash is used. 
ST_GEOMFROMTEXT(wkt) 
Returns a geometry from the given WellKnown text representation wkt . Note that this function is
only compatible with constants 
ST_HEXGRID(xmin, ymin, xmax, ymax, cell_side) 
Creates a MULTIPOLYGON containing a grid of hexagons between given minimum and maximum points of a
bounding box. The minimum point cannot be greater than or equal to the maximum point. The size (in
meters) of the individual hexagons' sides is determined by cell_side . The maximum number of cells
that can be produced is 20 million; if the request specifies more than that (based on the bounding box
and the cell_side ), a null is returned. The cell_side cannot be greater than the width or
height of the bounding box. 
ST_INTERIORRINGN(geom, n) 
Returns the n th interior LINESTRING ring of the POLYGON geom . If geom is not a POLYGON
or the given n is out of range, a null is returned. The index begins at 1 
ST_INTERSECTION(geom1, geom2) 
Returns the shared portion between given geometries geom1 and geom2 
ST_INTERSECTS(geom1, geom2) 
Returns 1 (true) if the given geometries, geom1 and geom2 , intersect in 2D 
ST_ISCLOSED(geom) 
Returns 1 (true) if the given geometry's (geom ) start and end points coincide 
ST_ISCOLLECTION(geom) 
Returns 1 (true) if geom is a collection, e.g., GEOMETRYCOLLECTION, MULTIPOINT,
MULTILINESTRING, etc. 
ST_ISEMPTY(geom) 
Returns 1 (true) if geom is empty 
ST_ISRING(geom) 
Returns 1 (true) if LINESTRING geom is both closed (per ST_ISCLOSED ) and "simple"
(per ST_ISSIMPLE ). Returns 0 if geom is not a LINESTRING 
ST_ISSIMPLE(geom) 
Returns 1 (true) if geom has no anomalous geometric points, e.g., selfintersection or
selftangency 
ST_ISVALID(geom) 
Returns 1 (true) if geom (typically a [MULTI]POLYGON) is well formed. A POLYGON is valid if
its rings do not cross and its boundary intersects only at POINTs (not along a line). The POLYGON must
also not have dangling LINESTRINGs. A MULTIPOLYGON is valid if all of its elements are also valid and
the interior rings of those elements do not intersect. Each element's boundaries may touch but only
at POINTs (not along a line) 
ST_LENGTH(geom[, solution]) 
Returns the length of the geometry if it is a LINESTRING or MULTILINESTRING. Returns

ST_LINEFROMMULTIPOINT(geom) 
Creates a LINESTRING from geom if it is a MULTIPOINT. Returns null if geom is not a
MULTIPOINT 
ST_LINEINTERPOLATEPOINT(geom, fraction) 
Returns a POINT that represents the specified fraction of the LINESTRING geom . If geom is
either empty or not a LINESTRING, null is returned 
ST_LINELOCATEPOINT(linestring, point) 
Returns the location of the closest point in the given linestring to the given point as a
value between 0 and 1 . The return value is a fraction of the total linestring length. 
ST_LINEMERGE(geom) 
Returns a LINESTRING or MULTILINESTRING from a given geom . If geom is a MULTILINESTRING
comprising LINESTRINGs with shared endpoints, a contiguous LINESTRING is returned. If geom is a
LINESTRING or a MULTILINESTRING comprising LINESTRINGS without shared endpoints, geom is returned
If geom is an empty (MULTI)LINESTRING or a (MULTI)POINT or (MULTI)POLYGON, an empty
GEOMETRYCOLLECTION is returned. 
ST_LINESUBSTRING(geom, start_fraction, end_fraction) 
Returns the fraction of a given geom LINESTRING where start_fraction and end_fraction are
between 0 and 1 . For example, given LINESTRING(1 1, 2 2, 3 3) a start_fraction of
0 and an end_fraction of 0.25 would yield the first quarter of the given LINESTRING, or
LINESTRING(1 1, 1.5 1.5) . Returns null if start_fraction is greater than
end_fraction . Returns null if input geometry is (MULTI)POINT, MULTILINESTRING, or
(MULTI)POLYGON. Returns null if start_fraction and/or end_fraction are less than 0 or
more than 1 . 
ST_LONGESTLINE(geom1, geom2[, solution]) 
Returns the LINESTRING that represents the longest line of points between the two geometries. If
multiple longest lines are found, only the first line found is returned. If

ST_MAKEENVELOPE(xmin, ymin, xmax, ymax) 
Creates a rectangular POLYGON from the given min and max parameters 
ST_MAKELINE(geom[, geom2]) 
Creates a LINESTRING from Note This function can be rather costly in terms of performance 
ST_MAKEPOINT(x, y) 
Creates a POINT at the given coordinate Note This function can be rather costly in terms of performance 
ST_MAKEPOLYGON(geom) 
Creates a POLYGON from Note This function can be rather costly in terms of performance 
ST_MAKETRIANGLE2D(x1, y1, x2, y2, x3, y3) 
Creates a closed 2D POLYGON with three vertices 
ST_MAKETRIANGLE3D(x1, y1, z1, x2, y2, z2,
x3, y3, z3) 
Creates a closed 3D POLYGON with three vertices 
ST_MAXDISTANCE(geom1, geom2[, solution]) 
Returns the maximum distance between the given

ST_MAXX(geom) 
Returns the maximum x coordinate of a bounding box for the given geom geometry. This function
works for 2D and 3D geometries. 
ST_MAXY(geom) 
Returns the maximum y coordinate of a bounding box for the given geom geometry. This function
works for 2D and 3D geometries. 
ST_MAXZ(geom) 
Returns the maximum z coordinate of a bounding box for the given geom geometry. This function
works for 2D and 3D geometries. 
ST_MINX(geom) 
Returns the minimum x coordinate of a bounding box for the given geom geometry. This function
works for 2D and 3D geometries. 
ST_MINY(geom) 
Returns the minimum y coordinate of a bounding box for the given geom geometry. This function
works for 2D and 3D geometries. 
ST_MINZ(geom) 
Returns the minimum z coordinate of a bounding box for the given geom geometry. This function
works for 2D and 3D geometries. 
ST_MULTI(geom) 
Returns geom as a MULTI geometry, e.g., a POINT would return a MULTIPOINT. 
ST_MULTIPLERINGBUFFERS(geom, distance, outside) 
Creates multiple buffers at specified

ST_NEAR(geom1, geom2) 
Returns the portion of geom2 that is closest to geom1 . If geom2 is a singular geometry
object (e.g., POINT, LINESTRING, POLYGON), geom2 will be returned. If geom2 a multigeometry,
e.g., MULTIPOINT, MULTILINESTRING, etc., the nearest singular geometry in geom2 will be
returned. 
ST_NORMALIZE(geom) 
Returns geom in its normalized (canonical) form, which may rearrange the points in lexicographical
order. 
ST_NPOINTS(geom) 
Returns the number of points (vertices) in geom . 
ST_NUMGEOMETRIES(geom) 
If geom is a collection or MULTI geometry, returns the number of geometries. If geom is a
single geometry, returns 1. 
ST_NUMINTERIORRINGS(geom) 
Returns the number of interior rings if geom is a POLYGON. Returns null if geom is
anything else. 
ST_NUMPOINTS(geom) 
Returns the number of points in the geom LINESTRING. Returns null if geom is not a
LINESTRING. 
ST_OVERLAPS(geom1, geom2) 
Returns 1 (true) if given geometries geom1 and geom2 share space. If geom1 and/or
geom2 are a GEOMETRYCOLLECTION, a 0 is returned regardless if the two geometries overlap 
ST_PARTITION(geom, threshold) 
Returns a MULTIPOLYGON representing the given geom partitioned into a number of POLYGONs with a
maximum number of vertices equal to the given threshold . Minimum value for threshold is
10 ; default value is 10000 . If geom is not a POLYGON or MULTIPOLYGON, geom is
returned. If the number of vertices in geom is less than the threshold , geom is returned. 
ST_PERIMETER(geom[, solution]) 
Returns the perimeter of the geometry if it is a POLYGON or MULTIPOLYGON. Returns

ST_POINT(x, y) 
Returns a POINT with the given x and y coordinates. 
ST_POINTFROMGEOHASH(geohash, precision) 
Returns a POINT using the given Note The POINT returned represents the center of the bounding box of the geohash 
ST_POINTGRID(xmin, ymin, xmax, ymax, cell_side) 
Creates a MULTIPOLYGON containing a squareshaped grid of points between given minimum and maximum
points of a bounding box. The minimum point cannot be greater than or equal to the maximum point. The
distance between the points (in meters) is determined by cell_side . The maximum number of cells
that can be produced is 20 million; if the request specifies more than that (based on the bounding box
and the cell_side ), a null is returned. The cell_side cannot be greater than the width or
height of the bounding box. 
ST_POINTN(geom, n) 
Returns the n th point in LINESTRING geom . Negative values are valid, but note that they are
counted backwards from the end of geom . A null is returned if geom is not a LINESTRING. 
ST_POINTS(geom) 
Returns a MULTIPOINT containing all of the coordinates of geom . 
ST_REMOVEPOINT(geom, offset) 
Remove a point from LINESTRING geom using offset to skip over POINTs in the LINESTRING. The
offset is 0based. 
ST_REMOVEREPEATEDPOINTS(geom, tolerance) 
Removes points from geom if the point's vertices are greater than or equal to the tolerance
of the previous point in the geometry's list. If geom is not a MULTIPOINT, MULTILINESTRING, or a
MULTIPOLYGON, no points will be removed. 
ST_REVERSE(geom) 
Return the geometry with its coordinate order reversed. 
ST_SCALE(geom, x, y) 
Scales geom by multiplying its respective vertices by the given x and y values.
This function also supports scaling geom using another geometry object, e.g.,
ST_SCALE('POINT(3 4)', 'POINT(5 6)') would return POINT(15 24) . If specifying x and y
for scale, note that the default value is 0 , e.g., ST_SCALE('POINT(1 3)', 4)
would return POINT(4 0) . 
ST_SEGMENTIZE(geom, max_segment_length[, solution]) 
Returns the given

ST_SETPOINT(geom1, position, geom2) 
Replace a point of LINESTRING geom1 with POINT geom2 at position (base 0). Negative
values are valid, but note that they are counted backwards from the end of geom . 
ST_SHAREDPATH(geom1, geom2) 
Returns a collection containing paths shared by geom1 and geom2 . 
ST_SHORTESTLINE(geom1, geom2) 
Returns the 2D LINESTRING that represents the shortest line of points between the two geometries. If
multiple shortest lines are found, only the first line found is returned. If geom1 or geom2
is empty, null is returned 
ST_SIMPLIFY(geom, tolerance) 
Returns a simplified version of the given Note The 
ST_SIMPLIFYPRESERVETOPOLOGY(geom, tolerance) 
Returns a simplified version of the given Note The 
ST_SNAP(geom1, geom2, tolerance) 
Snaps geom1 to geom2 within the given tolerance . If the tolerance causes geom1
to not snap, the geometries will be returned unchanged. 
ST_SPLIT(geom1, geom2) 
Returns a collection of geometries resulting from the split between geom1 and geom2
geometries. 
ST_SQUAREGRID(xmin, ymin, xmax, ymax, cell_side) 
Creates a MULTIPOLYGON containing a grid of squares between given minimum and maximum points of a
bounding box. The minimum point cannot be greater than or equal to the maximum point. The size (in
meters) of the individual squares' sides is determined by cell_side . The maximum number of cells
that can be produced is 20 million; if the request specifies more than that (based on the bounding box
and the cell_side ), a null is returned. The cell_side cannot be greater than the width or
height of the bounding box. 
ST_STARTPOINT(geom) 
Returns the first point of LINESTRING geom as a POINT. Returns null if geom is not a
LINESTRING. 
ST_SYMDIFFERENCE(geom1, geom2) 
Returns a geometry that represents the portions of geom1 and geom2 geometries that do not
intersect. 
ST_TOUCHES(geom1, geom2) 
Returns 1 (true) if the given geometries, geom1 and geom2 , have at least one point in
common but their interiors do not intersect. If geom1 and/or geom2 are a GEOMETRYCOLLECTION,
a 0 is returned regardless if the two geometries touch 
ST_TRANSLATE(geom, deltax, deltay[, deltaz]) 
Translate geom by given offsets deltax and deltay . A zcoordinate offset can be applied
using deltaz . 
ST_TRIANGLEGRID(xmin, ymin, xmax, ymax, cell_side) 
Creates a MULTIPOLYGON containing a grid of triangles between given minimum and maximum points of a
bounding box. The minimum point cannot be greater than or equal to the maximum point. The size (in
meters) of the individual triangles' sides is determined by cell_side . The maximum number of
cells that can be produced is 20 million; if the request specifies more than that (based on the
bounding box and the cell_side ), a null is returned. The cell_side cannot be greater than
the width or height of the bounding box. 
ST_UNION(geom1, geom2) 
Returns a geometry that represents the point set union of the two given geometries, geom1 and
geom2 . 
ST_UNIONCOLLECTION(geom) 
Returns a geometry that represents the point set union of a single given geometry geom . 
ST_UPDATE(geom1, geom2) 
Returns a geometry that is geom1 geometry updated by geom2 geometry 
ST_VORONOIPOLYGONS(geom, tolerance) 
Returns a GEOMETRYCOLLECTION containing Voronoi polygons (regions consisting of points closer to
a vertex in geom than any other vertices in geom ) calculated from the vertices in geom
and the given tolerance . The tolerance determines the distance at which points will be
considered the same. An empty GEOMETRYCOLLECTION is returned if geom is an empty geometry, a
single POINT, or a LINESTRING or POLYGON composed of equivalent vertices (e.g.,
POLYGON((0 0, 0 0, 0 0, 0 0)) , LINESTRING(0 0, 0 0) ). 
ST_WITHIN(geom1, geom2) 
Returns 1 (true) if the geom1 geometry is inside the geom2 geometry. Note that as long as
at least one point is inside of geom2 , geom1 is considered within geom2 even if the rest
of the geom1 lies along the boundary of geom2 
ST_WKTTOWKB(geom) 
Returns the binary form (WKB) of a Note This function can only be used in queries against a single table. 
ST_X(geom) 
Returns the X coordinate of the POINT geom ; if the coordinate is not available, null is
returned. geom must be a POINT. 
ST_XMAX(geom) 
Alias for ST_MAXX() 
ST_XMIN(geom) 
Alias for ST_MINX() 
ST_Y(geom) 
Returns the Y coordinate of the POINT geom ; if the coordinate is not available, null is
returned. geom must be a POINT. 
ST_YMAX(geom) 
Alias for ST_MAXY() 
ST_YMIN(geom) 
Alias for ST_MINY() 
ST_ZMAX(geom) 
Alias for ST_MAXZ() 
ST_ZMIN(geom) 
Alias for ST_MINZ() 
Function  Description 

ST_AGGREGATE_COLLECT(geom) 
Alias for ST_COLLECT_AGGREGATE() 
ST_AGGREGATE_INTERSECTION(geom) 
Alias for ST_INTERSECTION_AGGREGATE() 
ST_COLLECT_AGGREGATE(geom) 
Returns a GEOMETRYCOLLECTION comprising all geometries found in the geom set. Any MULTI* geometries will be
divided into separate singular geometries, e.g., MULTIPOINT((0 0), (1 1)) would be divided into POINT(0 0) and
POINT(1 1) in the results; the same is true for elements of a GEOMETRYCOLLECTION found in geom , where a
GEOMETRYCOLLECTION within the provided geom set will also be parsed, effectively flattening it and adding
the individual geometries to the resulting GEOMETRYCOLLECTION. Any empty geometries in geom are ignored
even if they are part of a GEOMETRYCOLLECTION. Any duplicate WKTs will be retained. 
ST_DISSOLVE(geom) 
Dissolves all geometries within a given set into a single geometry. Note that the resulting single geometry can still be a group of noncontiguous geometries but represented as a single group, e.g., a GEOMETRYCOLLECTION. Line geometries (LINESTRING, LINEARRING, and MULTILINESTRING) are ignored when calculating the resulting geometry. 
ST_INTERSECTION_AGGREGATE(geom) 
Returns a POLYGON or MULTIPOLYGON comprising the shared portion between all geometries found in the geom
set. Returns an empty GEOMETRYCOLLECTION if there is no shared portion between all geometries. Functionally
equivalent to ST_INTERSECTION(ST_INTERSECTION(ST_INTERSECTION(geom1, geom2), geom3), ... geomN) . 
ST_LINESTRINGFROMORDEREDPOINTS(x, y, t) 
Returns a LINESTRING that represents a "track" of the given points (x , y ) ordered by the given sort
column t (e.g., a timestamp or sequence number). If any of the values in the specified columns are
null , the null "point" will be left out of the resulting LINESTRING. If there's only one nonnull "point"
in the source table, a POINT is returned. If there are no nonnull "points" in the source table, a null is
returned 