获取数据库最新的一条打卡时间数据SQL语句

上班表创建SQL语句

CREATE TABLE "PunchIn" ("id" INT NOT NULL,"emp_code" VARCHAR(50) NOT NULL COLLATE 'Chinese_PRC_CI_AS',"punch_in_time" DATETIME NOT NULL,"status" VARCHAR(10) NOT NULL COLLATE 'Chinese_PRC_CI_AS',PRIMARY KEY ("id")
)
;

下班打卡时间表创建SQL语句

CREATE TABLE "PunchOut" ("id" INT NOT NULL,"emp_code" VARCHAR(50) NOT NULL COLLATE 'Chinese_PRC_CI_AS',"punch_out_time" DATETIME NOT NULL,"status" VARCHAR(10) NOT NULL COLLATE 'Chinese_PRC_CI_AS',PRIMARY KEY ("id")
)
;

员工信息表创建SQL语句

CREATE TABLE "Employee" ("id" INT NOT NULL,"emp_code" VARCHAR(50) NOT NULL COLLATE 'Chinese_PRC_CI_AS',"username" VARCHAR(50) NOT NULL COLLATE 'Chinese_PRC_CI_AS',"password" VARCHAR(50) NOT NULL COLLATE 'Chinese_PRC_CI_AS',PRIMARY KEY ("id")
)
;

⚠️注意在创建表时把这个去掉：COLLATE ‘Chinese_PRC_CI_AS’

实现获取最新的打卡下班时间SQL语句

SELECT * FROM (
SELECT a.id,a1.emp_code AS 工号, a1.username AS 用户名,CONVERT(VARCHAR(19), a.punch_in_time, 120) AS 上班打卡时间, a.status AS 上班打卡状态,CONVERT(VARCHAR(19), b.punch_out_time, 120) AS 下班打卡时间, b.status AS 下班打卡状态
FROM Employee a1 
LEFT JOIN PunchIn a 
ON a1.emp_code = a.emp_code
LEFT JOIN PunchOut b 
ON a.emp_code = b.emp_code AND CONVERT(DATE, a.punch_in_time) = CONVERT(DATE, b.punch_out_time)AND b.id = (SELECT MAX(id)FROM PunchOutWHERE emp_code = a.emp_code AND CONVERT(DATE, punch_out_time) = CONVERT(DATE, a.punch_in_time))
ORDER BY a.emp_code, a.punch_in_time
) main WHERE 下班打卡时间 IS NULL;