MySQL 全文检索
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 |
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) |
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