fix(druid): support current_timestamp (tobymao#5061)

* feat: added support for current_timestamp

* test: Added tests for current_timestamp

---------

Co-authored-by: Jo <[email protected]>

Author: ALongJohnson

sqlglot/dialects/druid.py

@@ -15,5 +15,6 @@ class Generator(generator.Generator):
 
         TRANSFORMS = {
             **generator.Generator.TRANSFORMS,
+            exp.CurrentTimestamp: lambda *_: "CURRENT_TIMESTAMP",
             exp.Mod: rename_func("MOD"),
         }

tests/dialects/test_druid.py

@@ -13,6 +13,7 @@ def test_druid(self):
         self.validate_identity("SELECT FLOOR(__time TO WEEK) FROM t")
         self.validate_identity("SELECT FLOOR(col) FROM t")
         self.validate_identity("SELECT FLOOR(price, 2) AS rounded_price FROM t")
+        self.validate_identity("SELECT CURRENT_TIMESTAMP")
 
         # validate across all dialects
         write = {dialect.value: "FLOOR(__time TO WEEK)" for dialect in Dialects}