mysql> select a.*, b.* from a inner join b on a.aa = b.ba;
+----+------+------+----+------+------+
| aa | ab | ac | ba | bb | bc |
+----+------+------+----+------+------+
| 1 | 100 | a1 | 1 | 100 | b1 |
| 3 | 300 | a3 | 3 | 300 | b2 |
| 5 | 500 | a5 | 5 | 500 | b3 |
+----+------+------+----+------+------+
3 rows in set (0.00 sec)
mysql> select a.*, b.* from a left outer join b on a.aa = b.ba;
+----+------+------+------+------+------+
| aa | ab | ac | ba | bb | bc |
+----+------+------+------+------+------+
| 1 | 100 | a1 | 1 | 100 | b1 |
| 2 | 200 | a2 | NULL | NULL | NULL |
| 3 | 300 | a3 | 3 | 300 | b2 |
| 4 | 400 | a4 | NULL | NULL | NULL |
| 5 | 500 | a5 | 5 | 500 | b3 |
+----+------+------+------+------+------+
5 rows in set (0.00 sec)
mysql> select a.*, b.* from a left join b on a.aa = b.ba;
+----+------+------+------+------+------+
| aa | ab | ac | ba | bb | bc |
+----+------+------+------+------+------+
| 1 | 100 | a1 | 1 | 100 | b1 |
| 2 | 200 | a2 | NULL | NULL | NULL |
| 3 | 300 | a3 | 3 | 300 | b2 |
| 4 | 400 | a4 | NULL | NULL | NULL |
| 5 | 500 | a5 | 5 | 500 | b3 |
+----+------+------+------+------+------+
5 rows in set (0.00 sec)
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