QUERY: CREATE TABLE LSEG_TBL (s lseg);
QUERY: INSERT INTO LSEG_TBL VALUES ('[(1,2),(3,4)]');
QUERY: INSERT INTO LSEG_TBL VALUES ('(0,0),(6,6)');
QUERY: INSERT INTO LSEG_TBL VALUES ('10,-10 ,-3,-4');
QUERY: INSERT INTO LSEG_TBL VALUES ('[-1e6,2e2,3e5, -4e1]');
QUERY: INSERT INTO LSEG_TBL VALUES ('(11,22,33,44)');
QUERY: INSERT INTO LSEG_TBL VALUES ('(3asdf,2 ,3,4r2)');
WARN:Bad lseg external representation '(3asdf,2 ,3,4r2)'
QUERY: INSERT INTO LSEG_TBL VALUES ('[1,2,3, 4');
WARN:Bad lseg external representation '[1,2,3, 4'
QUERY: INSERT INTO LSEG_TBL VALUES ('[(,2),(3,4)]');
WARN:Bad lseg external representation '[(,2),(3,4)]'
QUERY: INSERT INTO LSEG_TBL VALUES ('[(1,2),(3,4)');
WARN:Bad lseg external representation '[(1,2),(3,4)'
QUERY: select * from LSEG_TBL;
s                            
-----------------------------
[(1,2),(3,4)]                
[(0,0),(6,6)]                
[(10,-10),(-3,-4)]           
[(-1000000,200),(300000,-40)]
[(11,22),(33,44)]            
(5 rows)

QUERY: SELECT * FROM LSEG_TBL WHERE s <= '[(1,2),(3,4)]'::lseg;
NOTICE:there is no operator <= for types lseg and lseg
NOTICE:You will either have to retype this query using an
NOTICE:explicit cast, or you will have to define the operator
WARN:<= for lseg and lseg using CREATE OPERATOR
QUERY: SELECT * FROM LSEG_TBL WHERE (s <-> '[(1,2),(3,4)]'::lseg) < 10;
s                 
------------------
[(1,2),(3,4)]     
[(0,0),(6,6)]     
[(10,-10),(-3,-4)]
(3 rows)