The functions described in this section take two geometries as arguments and return a qualitative or quantitative relation between them.
The OpenGIS specification defines the a set of functions that
test the relationship between two geometry values. MySQL
originally implemented these functions such that they used
object minimum bounding rectangles (MBRs) and returned the
same result as the corresponding MBR-based functions. For
MBRContains() return the same result.
MBRCrosses() does not.)
Corresponding versions are available that use precise object
shapes. These versions are named with an
ST_ prefix. For example,
Contains() uses minimum
bounding rectangles, whereas
ST_Contains() uses object
There are also
ST_ aliases for existing
spatial functions that were already exact. For example,
ST_IsEmpty() is an alias for
A MySQL-specific set of MBR-based functions is available to test the relationship between two geometry values.