ST_MLineFromText(wkt [, srid]), ST_MultiLineStringFromText(wkt [,
srid])

Constructs a MultiLineString value using its WKT representation and
SRID.

If the geometry argument is NULL or not a syntactically well-formed
geometry, or if the SRID argument is NULL, the return value is NULL.

URL: https://dev.mysql.com/doc/refman/5.7/en/gis-wkt-functions.html

