yangshijie 71fd3a6b12 [feature](fe) support ANSI standard keyword for CURRENT_XXX #30550 ...

support ANSI standard keywords:

CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
LOCALTIME
LOCALTIMESTAMP
CURRENT_USER
mysql> SELECT CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, LOCALTIME, LOCALTIMESTAMP, CURRENT_USER;
+--------------+--------------+---------------------+-----------+---------------------+--------------+
| CURRENT_DATE | CURRENT_TIME | CURRENT_TIMESTAMP   | LOCALTIME | LOCALTIMESTAMP      | CURRENT_USER |
+--------------+--------------+---------------------+-----------+---------------------+--------------+
| 2024-01-31   | 03:53:20     | 2024-01-31 03:53:20 | 03:53:20  | 2024-01-31 03:53:20 | 'root'@'%'   |
+--------------+--------------+---------------------+-----------+---------------------+--------------+
1 row in set (0.07 sec)

2024-01-31 23:53:39 +08:00

..

main

[feature](fe) support ANSI standard keyword for CURRENT_XXX #30550

2024-01-31 23:53:39 +08:00

test

[enhance](Nereids): support DateLiteral with suffix space (#30583)

2024-01-31 23:53:39 +08:00