Tạo bảng và chèn ngày
mysql> CREATE TABLE DemoTable1376 (
-> AdmissionDate DATE
-> );
Query OK, 0 rows affected (0.68 sec)
mysql> INSERT INTO DemoTable1376 VALUES('2018-01-21');
mysql> INSERT INTO DemoTable1376 VALUES('2017-12-01');
mysql> INSERT INTO DemoTable1376 VALUES('2018-11-02');
mysql> INSERT INTO DemoTable1376 VALUES('2019-03-14');
Dữ liệu gốc
mysql> SELECT * FROM DemoTable1376;
+---------------+
| AdmissionDate |
+---------------+
| 2018-01-21 |
| 2017-12-01 |
| 2018-11-02 |
| 2019-03-14 |
+---------------+
Truy vấn: DATE_ADD lồng nhau
mysql> SELECT DATE_ADD(DATE_ADD(AdmissionDate, INTERVAL 1 YEAR), INTERVAL 2 DAY)
-> AS AfterAddingOneYearTwoDays
-> FROM DemoTable1376;
Kết quả
+---------------------------+
| AfterAddingOneYearTwoDays |
+---------------------------+
| 2019-01-23 |
| 2018-12-03 |
| 2019-11-04 |
| 2020-03-16 |
+---------------------------+
Mẹo: Có thể gộp: DATE_ADD(AdmissionDate, INTERVAL 1 YEAR + INTERVAL 2 DAY) hoặc dùng ADDDATE(AdmissionDate, INTERVAL '1 2' YEAR_DAY) (cú pháp đặc biệt).