MySQL 如何在MySQL表中使用CREATE TABLE语句生成多个虚拟COLUMNS?
在MySQL表中添加多个虚拟生成的列是完全可能的。可以通过以下示例进行说明。
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示例
mysql> Create table profit(cost int, price int, profit int AS (price-cost), price_revised int AS (price-2));
Query OK, 0 rows affected (0.73 sec)
mysql> Describe profit;
+---------------+---------+------+-----+---------+-------------------+
| Field | Type | Null | Key | Default | Extra |
+---------------+---------+------+-----+---------+-------------------+
| cost | int(11) | YES | | NULL | |
| price | int(11) | YES | | NULL | |
| profit | int(11) | YES | | NULL | VIRTUAL GENERATED |
| price_revised | int(11) | YES | | NULL | VIRTUAL GENERATED |
+---------------+---------+------+-----+---------+-------------------+
4 rows in set (0.00 sec)
mysql> Insert into profit(Cost, Price) values(100,110);
Query OK, 1 row affected (0.04 sec)
mysql> Insert into profit(Cost, Price) values(200,220);
Query OK, 1 row affected (0.04 sec)
mysql> Select * from profit;
+------+-------+--------+---------------+
| cost | price | profit | price_revised |
+------+-------+--------+---------------+
| 100 | 110 | 10 | 108 |
| 200 | 220 | 20 | 218 |
+------+-------+--------+---------------+
2 rows in set (0.00 sec)
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