Hiển thị tên cột distinct trong MySQL

Tạo bảng:

mysql> create table DemoTable1996 ( ShippingDate datetime, CustomerName varchar(20) ); Query OK, 0 rows affected (0.84 sec)

Thêm dữ liệu:

mysql> insert into DemoTable1996 values('2019-12-21 10:45:00','Chris'); Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable1996 values('2019-12-21 12:10:00','David'); Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable1996 values('2019-12-20 12:10:00','Bob'); Query OK, 1 row affected (0.14 sec)

Hiển thị dữ liệu:

mysql> select * from DemoTable1996;

+---------------------+--------------+
| ShippingDate        | CustomerName |
+---------------------+--------------+
| 2019-12-21 10:45:00 | Chris        |
| 2019-12-21 12:10:00 | David        |
| 2019-12-20 12:10:00 | Bob          |
+---------------------+--------------+
3 rows in set (0.00 sec)

Truy vấn nhóm theo ngày (bỏ phần giờ) để lấy hàng đại diện:

mysql> select * from DemoTable1996 group by date(ShippingDate);

Kết quả:

+---------------------+--------------+
| ShippingDate        | CustomerName |
+---------------------+--------------+
| 2019-12-21 10:45:00 | Chris        |
| 2019-12-20 12:10:00 | Bob          |
+---------------------+--------------+
2 rows in set (0.07 sec)