主要网站域名,什么网站可以做投资,企业网站建设与推广多少钱,php网站开发套模板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#xff0c;但是并非所有的引擎支持全文检索 #xff0c;目前最常用引擎是是MyISAM和InnoDB#xff1b;前者支持全文检索#xff0c;后者不支持。 booolean模式操作符 操作符含义必须有-必须不包含包含对应…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。 booolean模式操作符 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);
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| note_text |
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| 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. |
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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;
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| note_text | match_rank |
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| 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 |
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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);
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| note_text |
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| Customer complaint:
Not heavy enough to generate flying stars around head of victim. If being purchased for dropping, recommend ANV02 or ANV03 instead. |
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1 row in set (0.00 sec)
