32

您可以使用 RegEx 将逗号分隔的字符串解析为 MySQL 中的临时表吗?

'1|2|5|6' into temp table with 4 rows.
4

8 回答 8

39

这与Can Mysql Split a column几乎是同一个问题?

MySQL 没有拆分字符串功能,因此您必须解决问题。使用上面答案页面上列出的方法之一拆分数据后,您可以对数据执行任何操作。

您可以遍历该自定义函数并在它返回空时中断,您必须玩并学习一些语法(或者至少我会),但是 mysql 中 FOR 循环的语法在这里: http://www.roseindia .net/sql/mysql-example/for.shtml

您可以对其进行迭代,增加以下函数中的位置:

CREATE FUNCTION SPLIT_STR(
  x VARCHAR(255),
  delim VARCHAR(12),
  pos INT
)
RETURNS VARCHAR(255)
RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(x, delim, pos),
       LENGTH(SUBSTRING_INDEX(x, delim, pos -1)) + 1),
       delim, '');

(来源:https ://blog.fedecarg.com/2009/02/22/mysql-split-string-function/ )

如果未找到匹配项,则应返回 '',因此如果未找到匹配项,则中断循环。这将允许您仅使用 mysql 解析拆分字符串并将插入查询运行到临时表中。但是人为什么不直接使用像 php 这样的脚本语言来完成这种工作呢?:(

循环语法代码:

DELIMITER $$  

CREATE PROCEDURE ABC(fullstr)

   BEGIN
      DECLARE a INT Default 0 ;
      DECLARE str VARCHAR(255);
      simple_loop: LOOP
         SET a=a+1;
         SET str=SPLIT_STR(fullstr,"|",a);
         IF str='' THEN
            LEAVE simple_loop;
         END IF;
         #Do Inserts into temp table here with str going into the row
         insert into my_temp_table values (str);
   END LOOP simple_loop;
END $$
于 2012-08-06T20:14:59.043 回答
7

我找到了很好的解决方案

https://forums.mysql.com/read.php?10,635524,635529

感谢彼得布劳利

技巧:将 csv 字符串上的 Group_Concat() 结果按摩到 Insert...Values... 字符串中:

drop table if exists t;
create table t( txt text );
insert into t values('1,2,3,4,5,6,7,8,9');

drop temporary table if exists temp;
create temporary table temp( val char(255) );
set @sql = concat("insert into temp (val) values ('", replace(( select group_concat(distinct txt) as data from t), ",", "'),('"),"');");
prepare stmt1 from @sql;
execute stmt1;
select distinct(val) from temp;
+------+
| val  |
+------+
| 1    |
| 2    |
| 3    |
| 4    |
| 5    |
| 6    |
| 7    |
| 8    |
| 9    |
+------+

此外,如果您只想将某个表加入 id 列表,则可以使用 LIKE 运算符。有我的解决方案,我从博客文章 url 中获取 id 列表,将它们转换为逗号分隔的列表,以逗号开头和结尾,然后使用 LIKE 运算符通过 id 列表加入相关产品。

SELECT b2.id blog_id, b2.id_list, p.id
FROM (
    SELECT b.id,b.text,
    CONCAT(
        ",",
            REPLACE(
                EXTRACTVALUE(b.text,'//a/@id')
                , " ", ","
            )
        ,","
    ) AS id_list
    FROM blog b
) b2
LEFT JOIN production p ON b2.id_list LIKE CONCAT('%,',p.id,',%')
HAVING b2.id_list != ''
于 2018-05-24T09:02:41.503 回答
4
DELIMITER $$  

CREATE PROCEDURE SPLIT_VALUE_STRING()

    BEGIN

        SET @String      = '1,22,333,444,5555,66666,777777';
        SET @Occurrences = LENGTH(@String) - LENGTH(REPLACE(@String, ',', ''));
        myloop: WHILE (@Occurrences > 0)
        DO 
            SET @myValue = SUBSTRING_INDEX(@String, ',', 1);
            IF (@myValue != '') THEN
            /* my code... */
            ELSE
                LEAVE myloop; 
            END IF;
            SET @Occurrences = LENGTH(@String) - LENGTH(REPLACE(@String, ',', ''));
            IF (@occurrences = 0) THEN 
                LEAVE myloop; 
            END IF;
            SET @String = SUBSTRING(@String,LENGTH(SUBSTRING_INDEX(@String, ',', 1))+2);
        END WHILE;                  

   END $$
于 2014-08-13T09:42:49.733 回答
2

我已经这样做了,因为当您没有表值等时:

select *
from(
    select c, SUBSTRING_INDEX(SUBSTRING_INDEX('1|2|5|6', '|', c+1), '|', -1) as name
    from(
        SELECT (TWO_1.SeqValue + TWO_2.SeqValue + TWO_4.SeqValue + TWO_8.SeqValue + TWO_16.SeqValue + TWO_32.SeqValue) c
        FROM (
            SELECT 0 SeqValue UNION ALL SELECT 1 SeqValue) TWO_1
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 2 SeqValue) TWO_2
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 4 SeqValue) TWO_4
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 8 SeqValue) TWO_8
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 16 SeqValue) TWO_16 
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 32 SeqValue) TWO_32
    ) as b
    WHERE c <= (CHAR_LENGTH('1|2|5|6') - CHAR_LENGTH(REPLACE('1|2|5|6', '|', '')))
) as a;

可能不是最好的答案,但在没有函数和过程的帮助下工作,没有额外的表格等。

于 2016-07-04T16:27:49.870 回答
2
select distinct
  SUBSTRING_INDEX(SUBSTRING_INDEX('1,2,3,4', ',', numbers.n), ',', -1) name
from
  (select @rownum := @rownum + 1 as n
from YourTable
cross join (select @rownum := 0) r
) numbers 
order by
   n
于 2017-08-18T16:50:11.423 回答
1

您可以在 MySQL 中使用正则表达式来指定复杂搜索的模式,您无法解析字符串。

但是您可以在 REPLACE 和 CONCATENATE 的帮助下构建 INSERT 查询以将数据保存到临时表。

于 2012-08-06T20:15:34.597 回答
0

如果您尝试拆分的文本包含多字节字符,则此方法将因 LENGTH 计算不正确而失效。对于这种情况,使用 CHAR_LENGTH 而不是 LENGTH 的以下版本可以工作:

CREATE DEFINER=`root`@`localhost` FUNCTION `strSplit`(
           `src` MEDIUMTEXT CHARACTER SET utf8, 
           `delim` VARCHAR(12), 
           `pos` INTEGER
          )
    RETURNS mediumtext
    LANGUAGE SQL
    NOT DETERMINISTIC
    CONTAINS SQL
    SQL SECURITY DEFINER
    COMMENT ''
BEGIN
  DECLARE output MEDIUMTEXT CHARACTER SET utf8;
  SET output = REPLACE(SUBSTRING(SUBSTRING_INDEX(src, delim, pos) ,  
              CHAR_LENGTH(SUBSTRING_INDEX(src, delim, pos - 1)) + 1) , delim , '');
  IF output = '' THEN SET output = null; END IF;
  RETURN output;
END

参考:http ://www.shakedos.com/2011/Nov/23/mysql-split-string-function-fix-split_str.html

于 2015-12-17T18:02:20.207 回答
0

只是因为我真的很喜欢复活旧问题:

CREATE PROCEDURE `SPLIT_LIST_STR`(IN `INISTR` TEXT CHARSET utf8mb4, IN `ENDSTR` TEXT CHARSET utf8mb4, IN `INPUTSTR` TEXT CHARSET utf8mb4, IN `SEPARATR` TEXT CHARSET utf8mb4)
BEGIN
    SET @I = 1;
    SET @SEP = SEPARATR;
    SET @INI = INISTR;
    SET @END = ENDSTR;
    SET @VARSTR = REPLACE(REPLACE(INPUTSTR, @INI, ''), @END, '');
    SET @N = FORMAT((LENGTH(@VARSTR)-LENGTH(REPLACE(@VARSTR, @SEP, '')))/LENGTH(@SEP), 0)+1;

    CREATE TEMPORARY TABLE IF NOT EXISTS temp_table(P1 TEXT NULL);

    label1: LOOP
        SET @TEMP = SUBSTRING_INDEX(@VARSTR, @SEP, 1);
        insert into temp_table (`P1`) SELECT @TEMP;
        SET @I = @I + 1;
        SET @VARSTR = REPLACE(@VARSTR, CONCAT(@TEMP, @SEP), '');
        IF @N >= @I THEN
          ITERATE label1;
        END IF;
        LEAVE label1;
      END LOOP label1;
    SELECT * FROM temp_table;
    END

产生:

P1
1
2
3
4

使用时CALL SPLIT_LIST_STR('("', '")', '("1", "2", "3", "4")', '", "');

稍后我可能会弹出以使代码更潮一点!干杯!

于 2017-10-23T02:23:55.263 回答