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MySQL數據庫數據類型之集合類型SET測試總結(3)
+----+-------------+-----------+
| ID | Work_Option | Work_City |
+----+-------------+-----------+
| 3 | | hangzhou |
+----+-------------+-----------+
1 row in set (0.00 sec)
root@localhost : test 03:10:30> SELECT * FROM mysqlops_set WHERE Work_City=7;
+----+-------------+---------------------------+
| ID | Work_Option | Work_City |
+----+-------------+---------------------------+
| 8 | DBA,SA,NA | shanghai,beijing,hangzhou |
+----+-------------+---------------------------+
1 row in set (0.00 sec)
root@localhost : test 03:13:13> SELECT * FROM mysqlops_set WHERE Work_City=63;
+----+-------------+----------------------------------------------------+
| ID | Work_Option | Work_City |
+----+-------------+----------------------------------------------------+
| 9 | DBA,SA,NA | shanghai,beijing,hangzhou,shenzhen,guangzhou,other |
+----+-------------+----------------------------------------------------+
1 row in set (0.00 sec)
集合類型SET元素的存儲順序梳理：
l 集合類型字段定義的值域列表信息
|
集合類型值域列表順序 |
值域列表順序對應的元素值 |
存儲序號二進制編碼 |
二進制編碼對應的十進制值 |
|
1 |
shanghai |
0000,0001 |
1 |
|
2 |
beijing |
0000,0010 |
2 |
|
3 |
hangzhou |
0000,0100 |
4 |
|
4 |
shenzhen |
0000,1000 |
8 |
|
5 |
guangzhou |
0001,0000 |
16 |
|
6 |
other |
0010,0000 |
32 |
l 集合類型字段存儲的值
|
自增序列字段的值 |
集合類型字段Work_City的值 |
二進制編碼 |
十進制值 |
|
1 |
shanghai |
0000,0001 |
1 |
|
2 |
空格字符串 |
0000,0000 |
0 |
|
3 |
hangzhou |
0000,0100 |
4 |
|
4 |
空格字符串 |
0000,0000 |
0 |
|
5 |
shanghai |
0000,0001 |
1 |
|
6 |
shanghai |
0000,0001 |
1 |
|
7 |
Shanghai,beijing |
0000,0011 |
3 |
|
8 |
shanghai,beijing,hangzhou |
0000,0111 |
7 |
|
9 |
shanghai,beijing,hangzhou,shenzhen,guangzhou,other |
0011,1111 |
63 |
|
10 |
空格字符串 |
0000,0000 |
0 |
|
11 |
shanghai |
0000,0001 |
1 |
|
12 |
shanghai |
0000,0001 |
1 |
|
13 |
hangzhou |
0000,0100 |
4 |
|
20 |
shanghai,beijing |
0000,0011 |
3 |
原文轉自：http://blogread.cn/it/article/5114
