mysql 单表更新记录UPDATE

1、单表更新

（1）mysql> SELECT * FROM users;
+----+----------+----------+-----+------+
| id   | username | password | age | sex    |
+----+----------+----------+-----+------+
| 1   | Tom         | 123         | 25   | 1       |
| 2   | John         | 456         | 25   | 1       |
| 3   | Tom         | 123         | 25   | 1       |
| 4   | John         | 456         | 16   | 1       |
| 5   | John         | 456         | 10   | 1       |
| 10 | John         | 456         | 16   | 1       |
| 11 | ROSE        | 67          | 10   | 0        |
| 12 | Ben           | 456        | 10   | NULL  |
+----+----------+----------+-----+------+

mysql> UPDATE users SET age = age +5;  #更新一列

+----+----------+----------+-----+------+
| id   | username | password | age | sex    |
+----+----------+----------+-----+------+
| 1   | Tom         | 123         | 30   | 1       |
| 2   | John         | 456         | 30   | 1       |
| 3   | Tom         | 123         | 30   | 1       |
| 4   | John         | 456         | 21   | 1       |
| 5   | John         | 456         | 15   | 1       |
| 10 | John         | 456         | 21   | 1       |
| 11 | ROSE        | 67          | 15   | 0        |
| 12 | Ben           | 456        | 15   | NULL  |
+----+----------+----------+-----+------+

（2）更新多列

mysql> UPDATE users SET age = age -id, sex = 0;

mysql> SELECT * FROM users;
+----+----------+----------+-----+------+
| id | username | password | age | sex |
+----+----------+----------+-----+------+
| 1 | Tom | 123 | 29 | 0 |
| 2 | John | 456 | 28 | 0 |
| 3 | Tom | 123 | 27 | 0 |
| 4 | John | 456 | 17 | 0 |
| 5 | John | 456 | 10 | 0 |
| 10 | John | 456 | 11 | 0 |
| 11 | ROSE | 67 | 4 | 0 |
| 12 | Ben | 456 | 3 | 0 |
+----+----------+----------+-----+------+

（3）加限制条件
mysql> UPDATE users SET age = age +10 WHERE id % 2 = 0;

+----+----------+----------+-----+------+
| id | username | password | age | sex |
+----+----------+----------+-----+------+
| 1 | Tom | 123 | 29 | 0 |
| 2 | John | 456 | | 0 |
| 3 | Tom | 123 | 27 | 0 |
| 4 | John | 456 | | 0 |
| 5 | John | 456 | 10 | 0 |
| 10 | John | 456 | | 0 |
| 11 | ROSE | 67 | 4 | 0 |
| 12 | Ben | 456 | | 0 |
+----+----------+----------+-----+------+