MySQL-demo-統計各職業男女人數

• person表：

  • occupation職業：1學生，2老師，3醫生，4護士，5程序員
  • sex性別: 1男, 2女

  

• 結果：

  

• sql

SELECT
	CASE occupation
		WHEN 1 THEN
			'學生'
		WHEN 2 THEN
			'教師'
		WHEN 3 THEN
			'醫生'
		WHEN 4 THEN
			'護士'
		WHEN 5 THEN
			'程序員'
		ELSE
			'未知'
		END AS `職業`,
   CAST(
	  CONCAT(
	  	  '男:',
		  COUNT(IF(sex = 1, 1, NULL)),
		  ', 女:',
		  COUNT(IF(sex = 2, 1, NULL))
 	  ) AS CHAR
   ) AS `性別`
FROM
	`person`
GROUP BY
	occupation;
-- -----------------------------------------------------------------------------
SELECT
	CASE occupation
		WHEN 1 THEN
			'學生'
		WHEN 2 THEN
			'教師'
		WHEN 3 THEN
			'醫生'
		WHEN 4 THEN
			'護士'
		WHEN 5 THEN
			'程序員'
		ELSE
			'未知'
		END AS `職業`,
   COUNT(IF(sex = 1, 1, NULL)) AS '男',
   COUNT(IF(sex = 2, 1, NULL)) AS '女'
FROM
	`person`
GROUP BY
	occupation;