使用 JSON (MySQL/MariaDB) 替换字符串中的值

Question

我尝试了一种方法，但未成功，即使用包含 JSON 的列的值来替换仅使用 SQL 查询功能的字符串段。

下面是一些示例数据：


MariaDB [test_db]> SELECT * FROM events_log LIMIT 3;
+----+-------------------------------+----------------------+-----------------+----------------+-----------------+-----------+---------------------+------+
| id | textMessage                   | textMessageVariables | referenceColumn | referenceValue | referenceSource | createdBy | createdAt           | meta |
+----+-------------------------------+----------------------+-----------------+----------------+-----------------+-----------+---------------------+------+
|  1 | Data added (#%referenceCode%) | {"%referenceCode%":254}       | id              | 1              | surveys  |         1 | 2022-02-14 15:41:58 | {}   |
|  2 | Data added (#%referenceCode%) | {"%referenceCode%":354}       | id              | 2              | surveys  |         1 | 2022-02-14 15:42:09 | {}   |
|  3 | Data added (#%referenceCode%) | {"%referenceCode%":687}       | id              | 3              | surveys  |         5 | 2022-02-15 09:42:36 | {}   |
+----+-------------------------------+----------------------+-----------------+----------------+-----------------+-----------+---------------------+------+

期望的结果是能够使用 textMessageVariables 列中相应的 JSON 值替换 %referenceCode% 值，而不必专门声明每个替换，以便为 N 个变量保留通用解决方案.

提前致谢。

Answer 1

我终于能够修复它。我构建了一个相当简单的函数，成功地解决了这个需求。

SQL函数：

DELIMITER ;;

DROP FUNCTION IF EXISTS strTemplateReplace;;
CREATE FUNCTION strTemplateReplace(templateText text, replacementJSON text) RETURNS text CHARSET utf8
BEGIN
    DECLARE replacementKeys TEXT;
    DECLARE replacementQty INT UNSIGNED DEFAULT 0;
    DECLARE resultText TEXT;
    DECLARE counterVar INT UNSIGNED DEFAULT 0;
    DECLARE currentKey TEXT;
    DECLARE currentValue TEXT;
    SET replacementKeys = JSON_KEYS(replacementJSON);
    SET replacementQty = JSON_LENGTH(replacementJSON);
    SET resultText = templateText;

    WHILE counterVar < replacementQty DO
        SET currentKey = JSON_UNQUOTE(
            JSON_EXTRACT(
                replacementKeys,
                CONCAT('$[', counterVar, ']')
            )
        );
        SET currentValue = JSON_UNQUOTE(
            JSON_EXTRACT(
                replacementJSON,
                CONCAT('$.', currentKey)
            )
        );
        SET resultText = REPLACE(
            resultText,
            currentKey,
            currentValue
        );
        SET counterVar = counterVar + 1;
    END WHILE;

    RETURN ( resultText );
END;;

DELIMITER ;

结果符合预期：

MariaDB [test_db]> SELECT id, textMessage, textMessageVariables, strTemplateReplace(textMessage, textMessageVariables) AS replacementResult FROM events_log LIMIT 3;
+----+-------------------------------+----------------------+------------------------+
| id | textMessage                   | textMessageVariables | replacementResult      |
+----+-------------------------------+----------------------+------------------------+
|  1 | Data added (#%referenceCode%) | {"%referenceCode%":1}       | Data added (#1) |
|  2 | Data added (#%referenceCode%) | {"%referenceCode%":2}       | Data added (#2) |
|  3 | Data added (#%referenceCode%) | {"%referenceCode%":3}       | Data added (#3) |
+----+-------------------------------+----------------------+------------------------+
3 rows in set (0.002 sec)

注意：在 10.5.13-MariaDB-1:10.5.13+maria~focal 环境中完美运行。

使用 JSON (MySQL/MariaDB) 替换字符串中的值

Replacing values in a string using JSON (MySQL/MariaDB)

mysql

json

replace

mariadb