Amazon Redshift will no longer support the creation of new Python UDFs starting November 1, 2025. 
  If you would like to use Python UDFs, create the UDFs prior to that date. 
  Existing Python UDFs will continue to function as normal. For more information, see the
  
          blog post
        
ST_IsValid
ST_IsValid returns true if the 2D projection of the input geometry is valid. For more information about the definition of a valid geometry, see Geometric validity.
Syntax
ST_IsValid(geom)
Arguments
- geom
 - 
                     
A value of data type
GEOMETRYor an expression that evaluates to aGEOMETRYtype. 
Return type
BOOLEAN
If geom is null, then null is returned.
Examples
The following SQL checks if the specified polygon is valid. In this example, the polygon is invalid because the interior of the polygon isn't simply connected.
SELECT ST_IsValid(ST_GeomFromText('POLYGON((0 0,10 0,10 10,0 10,0 0),(5 0,10 5,5 10,0 5,5 0))'));
 st_isvalid
-----------
 false