MariaDB [devildb]> select cdt + 1;
ERROR 1054 (42S22): Unknown column 'cdt' in 'field list'
MariaDB [devildb]> select * from block;
+------+-----+------------+-------+--------+----------+
| blno | uno | cdt | dates | bl_rsn | unbl_rsn |
+------+-----+------------+-------+--------+----------+
| 1 | 5 | 2020-12-06 | 7 | null | null |
| 2 | 3 | 2020-12-06 | 1 | null | null |
| 3 | 2 | 2020-12-06 | 3 | null | null |
+------+-----+------------+-------+--------+----------+
3 rows in set (0.052 sec)
MariaDB [devildb]> select cdt + dates from block;
+-------------+
| cdt + dates |
+-------------+
| 20201213 |
| 20201207 |
| 20201209 |
+-------------+
3 rows in set (0.000 sec)
MariaDB [devildb]> select date_add(cdt, interval dates day) from block;
+-----------------------------------+
| date_add(cdt, interval dates day) |
+-----------------------------------+
| 2020-12-13 |
| 2020-12-07 |
| 2020-12-09 |
+-----------------------------------+
3 rows in set (0.056 sec)
MariaDB [devildb]> select * from block where now <= date_add(cdt, interval dates day);
ERROR 1054 (42S22): Unknown column 'now' in 'where clause'
MariaDB [devildb]> select * from block where now() <= date_add(cdt, interval dates day);
+------+-----+------------+-------+--------+----------+
| blno | uno | cdt | dates | bl_rsn | unbl_rsn |
+------+-----+------------+-------+--------+----------+
| 1 | 5 | 2020-12-06 | 7 | null | null |
| 3 | 2 | 2020-12-06 | 3 | null | null |
+------+-----+------------+-------+--------+----------+
2 rows in set (0.053 sec)
MariaDB [devildb]> select * from block where currdate() <= date_add(cdt, interval dates day);
ERROR 1305 (42000): FUNCTION devildb.currdate does not exist
MariaDB [devildb]> select * from block where curdate() <= date_add(cdt, interval dates day);
+------+-----+------------+-------+--------+----------+
| blno | uno | cdt | dates | bl_rsn | unbl_rsn |
+------+-----+------------+-------+--------+----------+
| 1 | 5 | 2020-12-06 | 7 | null | null |
| 2 | 3 | 2020-12-06 | 1 | null | null |
| 3 | 2 | 2020-12-06 | 3 | null | null |
+------+-----+------------+-------+--------+----------+
3 rows in set (0.053 sec)
MariaDB [devildb]> update block set cdt = '2020-12-05' where blno=2
-> ;
Query OK, 1 row affected (0.056 sec)
Rows matched: 1 Changed: 1 Warnings: 0
MariaDB [devildb]> select * from block;
+------+-----+------------+-------+--------+----------+
| blno | uno | cdt | dates | bl_rsn | unbl_rsn |
+------+-----+------------+-------+--------+----------+
| 1 | 5 | 2020-12-06 | 7 | null | null |
| 2 | 3 | 2020-12-05 | 1 | null | null |
| 3 | 2 | 2020-12-06 | 3 | null | null |
+------+-----+------------+-------+--------+----------+
3 rows in set (0.000 sec)
MariaDB [devildb]> select * from block where curdate() <= date_add(cdt, interval dates day);
+------+-----+------------+-------+--------+----------+
| blno | uno | cdt | dates | bl_rsn | unbl_rsn |
+------+-----+------------+-------+--------+----------+
| 1 | 5 | 2020-12-06 | 7 | null | null |
| 3 | 2 | 2020-12-06 | 3 | null | null |
+------+-----+------------+-------+--------+----------+
2 rows in set (0.001 sec)