Question

String x "3_SJ454FH";

我想将'3'（在_之前）存储在mysql的另一列中，并将'SJ454FH'（在_之后）存储在另一列中。我已经在存储过程中尝试过substring_index函数，但是没有起作用。那么，有什么方法可以在存储过程中存储这样的价值？？

CREATE DEFINER=`root`@`localhost` PROCEDURE `insert_csv`(_list MEDIUMTEXT)
BEGIN

DECLARE _next TEXT DEFAULT NULL;
DECLARE _nextlen INT DEFAULT NULL;
DECLARE _value TEXT DEFAULT NULL;

iterator:
LOOP
  -- exit the loop if the list seems empty or was null;
  -- this extra caution is necessary to avoid an endless loop in the proc.
  IF LENGTH(TRIM(_list)) = 0 OR _list IS NULL THEN
    LEAVE iterator;
  END IF;

  -- capture the next value from the list
  SET _next = SUBSTRING_INDEX(_list,'_',1);

  -- save the length of the captured value; we will need to remove this
  -- many characters + 1 from the beginning of the string 
  -- before the next iteration
  SET _nextlen = LENGTH(_next);

  -- trim the value of leading and trailing spaces, in case of sloppy CSV strings
  SET _value = TRIM(_next);

  -- insert the extracted value into the target table
  INSERT INTO t1 (c1) VALUES (_value);

  -- rewrite the original string using the `INSERT()` string function,
  -- args are original string, start position, how many characters to remove, 
  -- and what to "insert" in their place (in this case, we "insert"
  -- an empty string, which removes _nextlen + 1 characters)
  SET _list = INSERT(_list,1,_nextlen + 1,'');

END LOOP;

END

输出：

id|c1
-----------
1 |3
-----------
2 |SJ454FH
-----------

我已经尝试过这段代码，但是它存储在下一行。

Answer 1

您可以将以下查询的逻辑与INTO结合使用，以所需的值填充两个变量，然后在单独的调用中将其插入。

SELECT LEFT("3_SJ454FH", INSTR("3_SJ454FH", "_")-1) AS Prefix, 
       MID("3_SJ454FH", INSTR("3_SJ454FH", "_")+1, LENGTH("3_SJ454FH")) AS Tail

如何在MySQL中使用拆分功能或将拆分值存储在不同的列中？

1 个答案: