Question

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.

Answer 1

这与Can Mysql Split a column?

几乎相同

MySQL没有拆分字符串功能，所以你必须做解决方法。使用上面答案页面中列出的方法之一拆分后，您可以对数据执行任何操作。

你可以遍历那个自定义函数并在它返回空时中断，你必须播放并学习一些语法（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

你可以迭代它，增加下面函数中的位置：

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, '');

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

如果未找到匹配项，则返回''，如果未找到匹配项，则中断循环。这将允许您只对解析字符串进行mysql解析，并将插入查询运行到临时表中。但是为什么不仅仅使用像php那样的脚本语言进行那种工作呢？：（

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 $$

Answer 2

我已经这样做了，因为当你没有表值时等等：

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，但没有功能和程序的帮助，没有额外的表格等。

Answer 3

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。

Answer 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 $$

Answer 5

我找到了很好的解决方案

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

感谢Peter Brawley

技巧：将csv字符串上的Group_Concat（）结果按到一个插入...值...字符串：

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，如果您只想将某些表连接到id列表，则可以使用LIKE运算符。有我的解决方案，我从博客帖子网址获取id列表，将它们转换为逗号分隔列表开始并用逗号结束，然后通过id列表与LIKE运算符加入相关产品。

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 != ''

Answer 6

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

Answer 7

如果您尝试拆分的文本包含多字节字符，则此方法会因为LENGTH计算错误而中断。对于这种情况，使用CHAR_LENGTH而不是LENGTH的以下版本可以使用：

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

Answer 8

因为我真的喜欢复活旧问题：

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

哪个产生：

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

时

我可能会在以后弹出代码更多！干杯！

MySQL将逗号分隔的字符串拆分为临时表

8 个答案: