MySQL-demo-统计各职业男女人数

• person表：

  • occupation职业：1学生，2老师，3医生，4护士，5程序员
  • sex性别: 1男, 2女

  

• 结果：

  

• sql

SELECT
	CASE occupation
		WHEN 1 THEN
			'学生'
		WHEN 2 THEN
			'教师'
		WHEN 3 THEN
			'医生'
		WHEN 4 THEN
			'护士'
		WHEN 5 THEN
			'程序员'
		ELSE
			'未知'
		END AS `职业`,
   CAST(
	  CONCAT(
	  	  '男:',
		  COUNT(IF(sex = 1, 1, NULL)),
		  ', 女:',
		  COUNT(IF(sex = 2, 1, NULL))
 	  ) AS CHAR
   ) AS `性别`
FROM
	`person`
GROUP BY
	occupation;
-- -----------------------------------------------------------------------------
SELECT
	CASE occupation
		WHEN 1 THEN
			'学生'
		WHEN 2 THEN
			'教师'
		WHEN 3 THEN
			'医生'
		WHEN 4 THEN
			'护士'
		WHEN 5 THEN
			'程序员'
		ELSE
			'未知'
		END AS `职业`,
   COUNT(IF(sex = 1, 1, NULL)) AS '男',
   COUNT(IF(sex = 2, 1, NULL)) AS '女'
FROM
	`person`
GROUP BY
	occupation;