Categories:: 지리 공간 함수, 변환 함수

TRY_TO_GEOMETRY¶

Parses an input and returns a value of type GEOMETRY.

This function is essentially identical to TO_GEOMETRY except that it returns NULL when TO_GEOMETRY would issue an error.

See also:: TO_GEOMETRY

Syntax¶

Use one of the following:

TRY_TO_GEOMETRY( <varchar_expression> )

TRY_TO_GEOMETRY( <binary_expression> )

TRY_TO_GEOMETRY( <variant_expression> )

Arguments¶

varchar_expression

The argument must be a string expression that represents a valid geometric object in one of the following formats:

WKT (well-known text).
WKB (well-known binary) in hexadecimal format (without a leading 0x).
EWKT (extended well-known text).
EWKB (extended well-known binary) in hexadecimal format (without a leading 0x).
GeoJSON.

binary_expression

The argument must be a binary expression in WKB or EWKB format.

variant_expression

The argument must be an OBJECT in GeoJSON format.

Returns¶

The function returns a value of type GEOMETRY.

Usage Notes¶

Returns NULL if the input cannot be parsed as the appropriate supported format (WKT, WKB, EWKT, EWKB, GeoJSON).
For GeoJSON, WKT, and WKB input, the resulting GEOMETRY object has SRID set to 0. To change the SRID, pass the GEOMETRY object to ST_SETSRID, specifying the SRID that you want to set. ST_SETSRID returns the GEOMETRY object with that SRID set.

Examples¶

This shows a simple use of the TRY_TO_GEOMETRY function with VARCHAR data:

select try_to_geometry('INVALID INPUT');

+--------------------------------------+
| try_to_geometry('INVALID INPUT')     |
|--------------------------------------|
| NULL                                 |
+--------------------------------------+