MySQL學習足跡記錄06--數據過濾--LIKE搭配百分號（%）和下劃線（_）通配符 1.LIKE操作符 *%表示匹配任何字符出現任意次數（>=0) 為了便於觀察，先把prod_name字段的所有的數據列出
eg:
mysql> SELECT prod_name FROM products;
+----------------+
| prod_name |
+----------------+
| .5 ton anvil |
| 1 ton anvil |
| 2 ton anvil |
| Detonator |
| Bird seed |
| Carrots |
| Fuses |
| JetPack 1000 |
| JetPack 2000 |
| Oil can |
| Safe |
| Sling |
| TNT (1 stick) |
| TNT (5 sticks) |
+----------------+
14 rows in set (0.00 sec)
mysql> SELECT prod_name FROM products
-> WHERE prod_name LIKE 'jet%'; #檢索一任何"jet"開頭的數據
+--------------+
| prod_name |
+--------------+
| JetPack 1000 |
| JetPack 2000 |
+--------------+
2 rows in set (0.00 sec)
mysql> SELECT prod_name FROM products
-> WHERE prod_name LIKE '%anvil%';
#'%anvil%'表示匹配任何位置包含文本anvil的值
+--------------+
| prod_name |
+--------------+
| .5 ton anvil |
| 1 ton anvil |
| 2 ton anvil |
+--------------+
3 rows in set (0.00 sec)
mysql> SELECT prod_name FROM products
-> WHERE prod_name LIKE 's%e';
#找出以s開頭並一e結尾的所有產品
+-----------+ | prod_name | +-----------+ | Safe | +-----------+ 1 row in set (0.00 sec)*下劃線（_)通配符 用途與%一樣，但下劃線只匹配單個字符
eg:
mysql> SELECT prod_name FROM products
-> WHERE prod_name LIKE '_ ton anvil';
+-------------+
| prod_name |
+-------------+
| 1 ton anvil |
| 2 ton anvil |
+-------------+
2 rows in set (0.01 sec)
請對比%操作符的結果：
mysql> SELECT prod_name FROM products
-> WHERE prod_name LIKE '% ton anvil';
+--------------+
| prod_name |
+--------------+
| .5 ton anvil |
| 1 ton anvil |
| 2 ton anvil |
+--------------+
3 rows in set (0.00 sec)
