mysql5.7版本的explain解析

先在mysql中建个表：

CREATE TABLE `t_user`  (
  `id` int(6) NOT NULL AUTO_INCREMENT,
  `name` varchar(30) CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL,
  `age` int(4) NOT NULL DEFAULT 20,
  `address` varchar(30) CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL default ‘‘,
  `create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `version` int(4) NOT NULL DEFAULT 0,
  PRIMARY KEY (`id`) USING BTREE,
  UNIQUE INDEX `idx_name`(`name`) USING BTREE,
  INDEX `idx_age_address`(`age`, `address`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 15 CHARACTER SET = latin1 COLLATE = latin1_swedish_ci ROW_FORMAT = DYNAMIC;

这个DDL创建了3个B+tree索引，我都用黄色背景标出来了。现在开始使用explain对各种查询进行分析：

1、type = ALL 是全表扫描

EXPLAIN select * from t_user; -- 全表扫描

end.

mysql5.7版本的explain解析

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