mysql怎么精确查找 mysql如何查找数据

mysql url encode编码后怎么精确搜索

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DELIMITER ;

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DROP FUNCTION IF EXISTS urlencode;

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DELIMITER |

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CREATE FUNCTION urlencode (s VARCHAR(4096)) RETURNS VARCHAR(4096)08.

DETERMINISTIC

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CONTAINS SQL

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BEGIN

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DECLARE c VARCHAR(4096) DEFAULT '';

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DECLARE pointer INT DEFAULT 1;

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DECLARE s2 VARCHAR(4096) DEFAULT '';

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IF ISNULL(s) THEN

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RETURN NULL;

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ELSE

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SET s2 = '';

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WHILE pointer = length(s) DO

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SET c = MID(s,pointer,1);

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IF c = ' ' THEN

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SET c = '+';

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ELSEIF NOT (ASCII(c) BETWEEN 48 AND 57 OR24.

ASCII(c) BETWEEN 65 AND 90 OR

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ASCII(c) BETWEEN 97 AND 122) THEN

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SET c = concat("%",LPAD(CONV(ASCII(c),10,16),2,0));27.

END IF;

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SET s2 = CONCAT(s2,c);

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SET pointer = pointer + 1;

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END while;

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END IF;

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RETURN s2;

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END;

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|

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DELIMITER ;

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DROP FUNCTION IF EXISTS urldecode;

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DELIMITER |

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CREATE FUNCTION urldecode (s VARCHAR(4096)) RETURNS VARCHAR(4096)06.

DETERMINISTIC

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CONTAINS SQL

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BEGIN

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DECLARE c VARCHAR(4096) DEFAULT '';

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DECLARE pointer INT DEFAULT 1;

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DECLARE h CHAR(2);

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DECLARE h1 CHAR(1);

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DECLARE h2 CHAR(1);

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DECLARE s2 VARCHAR(4096) DEFAULT '';

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IF ISNULL(s) THEN

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RETURN NULL;

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ELSE

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SET s2 = '';

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WHILE pointer = LENGTH(s) DO

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SET c = MID(s,pointer,1);

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IF c = '+' THEN

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SET c = ' ';

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ELSEIF c = '%' AND pointer + 2 = LENGTH(s) THEN25.

SET h1 = LOWER(MID(s,pointer+1,1));

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SET h2 = LOWER(MID(s,pointer+2,1));

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IF (h1 BETWEEN '0' AND '9' OR h1 BETWEEN 'a' AND 'f')28.

AND

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(h2 BETWEEN '0' AND '9' OR h2 BETWEEN 'a' AND 'f')30.

THEN

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SET h = CONCAT(h1,h2);

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SET pointer = pointer + 2;

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SET c = CHAR(CONV(h,16,10));

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END IF;

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END IF;

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SET s2 = CONCAT(s2,c);

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SET pointer = pointer + 1;

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END while;

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END IF;

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RETURN s2;

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END;

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|

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DELIMITER ;

当一个字符串经过多次 urlencode 处理之后，可以使用 multiurldecode来解码，它将多次调用 urldecode来解码，直到没有需要解码的字符

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DELIMITER ;

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DROP FUNCTION IF EXISTS multiurldecode;

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DELIMITER |

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CREATE FUNCTION multiurldecode (s VARCHAR(4096)) RETURNS VARCHAR(4096)08.

DETERMINISTIC

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CONTAINS SQL

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BEGIN

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DECLARE pr VARCHAR(4096) DEFAULT '';

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IF ISNULL(s) THEN

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RETURN NULL;

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END IF;

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REPEAT

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SET pr = s;

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SELECT urldecode(s) INTO s;

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UNTIL pr = s END REPEAT;

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RETURN s;

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END;

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|

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DELIMITER ;

mysql如何精确查找关键词，只提取最近5分钟内记录？

这个要看你具体的记录是创建日期的格式是人什么样的，假如，你的记录的是 unix 时间戳，

SELECT * FROM t WHERE (unix_timestamp(NOW()) - create_time) 300;

mysql中如何查询带%的字符

可以直接精确查询：

select * from test where name ='%a' -------------查询name为 %a的数据

模糊查询 select * from test where name like '%\%a%'; -----------模糊查询name中包含 %a的数据