不是所有的数据表都支持全文检索 MySQL支持多种底层数据库引擎，但是并非所有的引擎支持全文检索 ，目前最常用引擎是是MyISAM和InnoDB；前者支持全文检索，后者不支持。
| 操作符 | 含义 |
| + | 必须有 |
| - | 必须不包含 |
| > | 包含对应关键字的排名靠前 |
| < | 包含对应关键字的排名靠后 |
| ~ | 取反（） |
| * | 放在词尾 类似通配符 |
| " " | 引号中间作为一个完整的值处理 |
实验：
表productnotes ：
1.查询包含rabbit的行，并按照相关性排序
mysql> SELECT note_text
-> FROM productnotes
-> WHERE Match(note_text) Against('rabbit');
+----------------------------------------------------------------------------------------------------------------------+
| note_text |
+----------------------------------------------------------------------------------------------------------------------+
| Customer complaint: rabbit has been able to detect trap, food apparently less effective now. |
| Quantity varies, sold by the sack load. All guaranteed to be bright and orange, and suitable for use as rabbit bait. |
+----------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.01 sec)
2.显示每一条的相关性值
mysql> SELECT note_text,
-> Match(note_text) Against('rabbit') AS match_rank
-> FROM productnotes;
+-----------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------+
| note_text | match_rank |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------+
| Customer complaint:
Sticks not individually wrapped, too easy to mistakenly detonate all at once.
Recommend individual wrapping. | 0 |
| Can shipped full, refills not available.
Need to order new can if refill needed. | 0 |
| Safe is combination locked, combination not provided with safe.
This is rarely a problem as safes are typically blown up or dropped by customers. | 0 |
| Quantity varies, sold by the sack load.
All guaranteed to be bright and orange, and suitable for use as rabbit bait. | 1.5905543565750122 |
| Included fuses are short and have been known to detonate too quickly for some customers.
Longer fuses are available (item FU1) and should be recommended. | 0 |
| Matches not included, recommend purchase of matches or detonator (item DTNTR). | 0 |
| Please note that no returns will be accepted if safe opened using explosives. | 0 |
| Multiple customer returns, anvils failing to drop fast enough or falling backwards on purchaser. Recommend that customer considers using heavier anvils. | 0 |
| Item is extremely heavy. Designed for dropping, not recommended for use with slings, ropes, pulleys, or tightropes. | 0 |
| Customer complaint: rabbit has been able to detect trap, food apparently less effective now. | 1.6408053636550903 |
| Shipped unassembled, requires common tools (including oversized hammer). | 0 |
| Customer complaint:
Circular hole in safe floor can apparently be easily cut with handsaw. | 0 |
| Customer complaint:
Not heavy enough to generate flying stars around head of victim. If being purchased for dropping, recommend ANV02 or ANV03 instead. | 0 |
| Call from individual trapped in safe plummeting to the ground, suggests an escape hatch be added.
Comment forwarded to vendor. | 0 |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------+
14 rows in set (0.00 sec)
3.有heavy 但是没有rope
mysql> SELECT note_text
-> FROM productnotes
-> WHERE Match(note_text)
-> Against('heavy -rope*' IN BOOLEAN MODE);
+---------------------------------------------------------------------------------------------------------------------------------------------------------+
| note_text |
+---------------------------------------------------------------------------------------------------------------------------------------------------------+
| Customer complaint:
Not heavy enough to generate flying stars around head of victim. If being purchased for dropping, recommend ANV02 or ANV03 instead. |
+---------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
