MySQL 编写出某列数据所占总和百分比 SQL实例

SET NAMES utf8;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for person_base_info
-- ----------------------------
DROP TABLE IF EXISTS `person_base_info`;
CREATE TABLE `person_base_info`  (
  `uuid` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `address` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `email` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`uuid`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;

-- ----------------------------
-- Records of person_base_info
-- ----------------------------
INSERT INTO `person_base_info` VALUES ('w1e2233rf', '5', '深圳', '[email protected]');
INSERT INTO `person_base_info` VALUES ('we33212', '2', '深圳', '[email protected]');
INSERT INTO `person_base_info` VALUES ('we33rf', '1', '深圳', '[email protected]');
INSERT INTO `person_base_info` VALUES ('we5663rf', '4', '北京', '[email protected]');
INSERT INTO `person_base_info` VALUES ('wewq33rf', '3', '深圳', '[email protected]');

SET FOREIGN_KEY_CHECKS = 1;

查询出所有数据:

SELECT  *   FROM person_base_info

 查询地址所占比:

SELECT
a.address,
a.cont AS countAddress,
b.sum AS sumAddress,
CONCAT( ROUND( a.cont / b.sum * 100, 2 ), '', '%' ) AS percent 
FROM
( SELECT address, COUNT( address ) AS cont FROM person_base_info GROUP BY address ) a,(
SELECT
COUNT(*) AS sum 
FROM
person_base_info 
) b

SQL函数解释：

MySQL ROUND(x) 函数返回最接近于参数 x 的整数；ROUND(x,y) 函数对参数x进行四舍五入的操作，返回值保留小数点后面指定的y位。

MySQL CONCAT（）函数用于将多个字符串连接成一个字符串。