MySQL查询字段类型为json的数据

测试表如下：

/*
 Navicat Premium Data Transfer
 Source Server         :
 Source Server Type    : MySQL
 Source Server Version : 50717
 Source Host           : localhost:3306
 Source Schema         : ceshi
 Target Server Type    : MySQL
 Target Server Version : 50717
 File Encoding         : 65001
 Date: 19/07/2019 15:08:52
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for infojson
-- ----------------------------
DROP TABLE IF EXISTS `infojson`;
CREATE TABLE `infojson`  (
  `id` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `info` json NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of infojson
-- ----------------------------
INSERT INTO `infojson` VALUES ('1', '{\"sex\": \"male\", \"username\": \"wangermazi\"}');
SET FOREIGN_KEY_CHECKS = 1;

• 获取infojson表中username的值，查询方法有：

select infojson.id, json_extract(infojson.info, '$.username') as username from infojson;

结果如下：

  id   username
  1   "wangermazi"

• 以上这条sql查出的username的值是带有双引号的，但是有时我们不需要双引号，此时就需要用到下面这种方式：

select infojson.id, infojson.info ->> '$.username' as username from infojson;

结果如下：

  id   username
  1   wangermazi