1
1
1
1
1
1
- ON NULL -
- inner -
- left -
1	0
2	0
- right -
0	2
0	3
- full -
0	2
0	3
1	0
2	0
- inner -
- left -
1	\N
2	\N
- right -
\N	2
\N	3
- full -
\N	2
\N	3
1	\N
2	\N