php - #1054 mysql 过程中字段列表中的未知列

Question

我的表名称为“tmp1”，其中包含字段名称 id 和逗号。逗号包含 1,3,2,4,5 个文本数据类型的值。

我想要在我的存储过程中循环中单独的值。就像 1 然后 3 然后 2 等等。所以，我是按照给定的过程创建的。

BEGIN
DECLARE my_delimiter CHAR(1);
DECLARE split_comma text;
DECLARE done INT;
DECLARE occurance INT;
DECLARE i INT;
DECLARE id INT;
DECLARE sel_query VARCHAR(500);
DECLARE splitter_cur CURSOR FOR SELECT id,comma from tmp1;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;

OPEN splitter_cur;
    splitter_loop:LOOP
        FETCH splitter_cur INTO id,split_comma;
        SET occurance = LENGTH(split_comma) - LENGTH(REPLACE(split_comma,',',''))+1;
        SET my_delimiter=',';

        IF done = 1 THEN
            LEAVE splitter_loop;
        END IF;

        IF occurance > 0 THEN               
            SET i = 1;              
            WHILE i <= occurance DO
                SET sel_query = "SELECT SUBSTRING_INDEX(comma,',',i) as abc from tmp1"; 
                SET @sel_query = sel_query;
                PREPARE sel_query FROM @sel_query;      
                EXECUTE sel_query;                  
                SET i = i + 1;
            END WHILE;
        END IF;
        SET occurance = 0;
    END LOOP;
CLOSE splitter_cur;
END;

但是当我执行此过程时，出现错误“MySQL said: #1054 - 'field list' 中的未知列 'i'”

但这里的 i 是一个用于旋转循环的变量。

有什么解决办法吗？请帮助我...提前谢谢您...

Answer 1

您必须在查询中嵌入变量 i 的值，但您没有这样做。

更改:

SET sel_query = "SELECT SUBSTRING_INDEX(comma,',',i) as abc from tmp1"; 
SET @sel_query = sel_query;

致:

SET @sel_query = CONCAT( "SELECT SUBSTRING_INDEX(comma,',',", i, ") as abc from tmp1 )";