SELECT get_json_string('[{"k1":"v1"}, {"k2":"v2"}, {"k1":"v3"}, {"k1":"v4"}]', '$.k1');

SELECT get_json_string('[{"k1":"v1"}, {"k2":"v2"}, {"k1":"v3"}, {"k1":"v4"}]', '$.k1');

对于 json 文档:
'[{"k1":"v1"}, {"k2":"v2"}, {"k1":"v3"}, {"k1":"v4"}]'
其 root 是一个数组,但是 path '$.k1' 对应的应该是访问 object 的 k1 字段,所以无法匹配到,参考 mysql 8.0 的结果:
