0<=>0	0.0<=>0.0	"A"<=>"A"	NULL<=>NULL
1	1	1	1
1<=>0	0<=>NULL	NULL<=>0
0	0	0
1.0<=>0.0	0.0<=>NULL	NULL<=>0.0
0	0	0
"A"<=>"B"	"A"<=>NULL	NULL<=>"A"
0	0	0
id	value	id	value	t1.value<=>t2.value
1	NULL	1	NULL	1
id	value
1	NULL
id	value
1	NULL
id	value