The functions described in this section take two geometries as arguments and return a qualitative or quantitative relation between them.
The OpenGIS specification defines 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 example,
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.