外鍵trade.ticker_id指向ticker.id。從table1中查找table2中有零行的外鍵鏈接到的外鍵
我想查找'ticker'中所有行中'零交易'中有零行的鏈接。
mysql> describe trade;
+-----------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| time | datetime | NO | | NULL | |
| price | float | NO | | NULL | |
| quantity | int(11) | NO | | NULL | |
| source | varchar(64) | YES | | NULL | |
| buyer | varchar(64) | YES | | NULL | |
| seller | varchar(64) | YES | | NULL | |
| initiator | varchar(64) | YES | | NULL | |
| ticker_id | int(11) | YES | MUL | NULL | |
+-----------+-------------+------+-----+---------+----------------+
9 rows in set (0,00 sec)
mysql> describe ticker;
+-------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(64) | NO | | NULL | |
| long_name | varchar(250) | YES | | NULL | |
| exchange_id | int(11) | YES | MUL | NULL | |
+-------------+--------------+------+-----+---------+----------------+
4 rows in set (0,00 sec)
注意,錢是正常DECIMAL – Strawberry
我想它不會浮動,如果這是一家銀行,但對於我的應用來說,這是最好的。我使用Matlab來分析股價。 – ni9e