① 求救，mysql怎么解析json
DELIMITER $$ USE `dw`$$ DROP FUNCTION IF EXISTS `fn_Json_getKeyValue`$$ CREATE DEFINER=`data`@`%` FUNCTION `fn_Json_getKeyValue`( in_JsonArray VARCHAR(4096),#JSON数组字符串 in_Index TINYINT, #JSON对象序号，序号从1开始 in_KeyName VARCHAR(64)#键名 ) RETURNS VARCHAR(512) CHARSET utf8 BEGIN DECLARE vs_return VARCHAR(4096); DECLARE vs_JsonArray, vs_Json, vs_KeyName VARCHAR(4096); #declare vs_Json varchar(4096); DECLARE vi_pos1, vi_pos2 SMALLINT UNSIGNED; #写监控日志 #insert into dw.t_etl_log(sp_name, title, description) #values('dw.fn_Json_getKeyValue', '通过Json键名取键值', concat('in_JsonArray=', in_JsonArray)); SET vs_JsonArray = TRIM(in_JsonArray); SET vs_KeyName = TRIM(in_KeyName); IF vs_JsonArray = '' OR vs_JsonArray IS NULL OR vs_KeyName = '' OR vs_KeyName IS NULL OR in_Index 0 THEN #如果键名存在 SET vi_pos1 = vi_pos1 + CHAR_LENGTH(vs_KeyName); SET vi_pos2 = LOCATE(',', vs_json, vi_pos1); IF vi_pos2 = 0 THEN #最后一个元素没有','分隔符，也没有结束符'}' SET vi_pos2 = CHAR_LENGTH(vs_json) + 1; END IF; SET vs_return = REPLACE(MID(vs_json, vi_pos1, vi_pos2 - vi_pos1), '"', ''); END IF; END IF; END IF; RETURN(vs_return); END$$ DELIMITER ; 测试： {"old_current_score":"2","new_current_score":"0","old_grade_id":"1","new_grade_id":"1","grade_time":"2016-04-09 00:43:26","grade_upgrade_time":"2017-04-09 00:43:26"} select fn_Json_getKeyValue(reason,1,'old_grade_id')
② mysql5.7以下怎么解析json
DELIMITER $$
USE `dw`$$
DROP FUNCTION IF EXISTS `fn_Json_getKeyValue`$$
CREATE DEFINER=`data`@`%` FUNCTION `fn_Json_getKeyValue`(
in_JsonArray VARCHAR(4096),#JSON数组字符串
in_Index TINYINT, #JSON对象序号，序号从1开始
in_KeyName VARCHAR(64)#键名
) RETURNS VARCHAR(512) CHARSET utf8
BEGIN
DECLARE vs_return VARCHAR(4096);
DECLARE vs_JsonArray, vs_Json, vs_KeyName VARCHAR(4096);
#declare vs_Json varchar(4096);
DECLARE vi_pos1, vi_pos2 SMALLINT UNSIGNED;
#写监控日志
#insert into dw.t_etl_log(sp_name, title, description)
#values('dw.fn_Json_getKeyValue', '通过Json键名取键值', concat('in_JsonArray=', in_JsonArray));
SET vs_JsonArray = TRIM(in_JsonArray);
SET vs_KeyName = TRIM(in_KeyName);
IF vs_JsonArray = '' OR vs_JsonArray IS NULL
OR vs_KeyName = '' OR vs_KeyName IS NULL
OR in_Index <= 0 OR in_Index IS NULL THEN
SET vs_return = NULL;
ELSE
#去掉方括号
SET vs_JsonArray = REPLACE(REPLACE(vs_JsonArray, '[', ''), ']', '');
#取指定的JSON对象
SET vs_json = SUBSTRING_INDEX(SUBSTRING_INDEX(vs_JsonArray,'}', in_index),'}',-1);
IF vs_json = '' OR vs_json IS NULL THEN
SET vs_return = NULL;
ELSE
SET vs_KeyName = CONCAT('"', vs_KeyName, '":');
SET vi_pos1 = INSTR(vs_json, vs_KeyName);
IF vi_pos1 > 0 THEN
#如果键名存在
SET vi_pos1 = vi_pos1 + CHAR_LENGTH(vs_KeyName);
SET vi_pos2 = LOCATE(',', vs_json, vi_pos1);
IF vi_pos2 = 0 THEN
#最后一个元素没有','分隔符，也没有结束符'}'
SET vi_pos2 = CHAR_LENGTH(vs_json) + 1;
END IF;
SET vs_return = REPLACE(MID(vs_json, vi_pos1, vi_pos2 - vi_pos1), '"', '');
END IF;
END IF;
END IF;
RETURN(vs_return);
END$$
DELIMITER ;
测试： {"old_current_score":"2","new_current_score":"0","old_grade_id":"1","new_grade_id":"1","grade_time":"2016-04-09 00:43:26","grade_upgrade_time":"2017-04-09 00:43:26"}
select fn_Json_getKeyValue(reason,1,'old_grade_id');