如何将 1 个表中的 2 个值加入 1 行？

Question

I have a table named log_attendance

Output needed:

thank's for any help

Answer 1

A simple approach to this, would be using GROUP BY clause by the emp_id column and then play with the aggregate methods MAX() and MIN() for get the desired result. Note that, for mapping to NULL values you will need to do an extra check, like this:

SELECT
    emp_id,
    MIN(tap_in) AS tap_in,
    IF(MIN(tap_in) = MAX(tap_in), NULL, MAX(tap_in)) AS tap_out
FROM
    log_attendance
GROUP BY
    emp_id

You can check it here also: DB-Fiddle

Answer 2

You may have to use GROUP BY with MIN and MAX function to achieve your requirements.

SELECT emp_id,
       MIN(tap_in) AS tap_in,
       MAX(tap_in) tap_out
FROM TABLE
GROUP BY emp_id

Answer 3

Please see the below simple query

SELECT empid,
   min([tap In]) [tap In] ,CASE WHEN  min([tap In])= max([tap In]) THEN NULL ELSE max([tap In]) END [tap out] 
FROM
    log_attendance 
 GROUP BY empid