1 files changed, 24 insertions, 1 deletions
diff --git a/sqlglot/dialects/dialect.py b/sqlglot/dialects/dialect.py
index 1d0584c..132496f 100644
--- a/sqlglot/dialects/dialect.py
+++ b/sqlglot/dialects/dialect.py
@@ -39,6 +39,7 @@ class Dialects(str, Enum):
     TERADATA = "teradata"
     TRINO = "trino"
     TSQL = "tsql"
+    Doris = "doris"
 
 
 class _Dialect(type):
@@ -121,7 +122,7 @@ class _Dialect(type):
                 if hasattr(subclass, name):
                     setattr(subclass, name, value)
 
-        if not klass.STRICT_STRING_CONCAT:
+        if not klass.STRICT_STRING_CONCAT and klass.DPIPE_IS_STRING_CONCAT:
             klass.parser_class.BITWISE[TokenType.DPIPE] = exp.SafeDPipe
 
         klass.generator_class.can_identify = klass.can_identify
@@ -146,6 +147,9 @@ class Dialect(metaclass=_Dialect):
     # Determines whether or not an unquoted identifier can start with a digit
     IDENTIFIERS_CAN_START_WITH_DIGIT = False
 
+    # Determines whether or not the DPIPE token ('||') is a string concatenation operator
+    DPIPE_IS_STRING_CONCAT = True
+
     # Determines whether or not CONCAT's arguments must be strings
     STRICT_STRING_CONCAT = False
 
@@ -460,6 +464,20 @@ def format_time_lambda(
     return _format_time
 
 
+def time_format(
+    dialect: DialectType = None,
+) -> t.Callable[[Generator, exp.UnixToStr | exp.StrToUnix], t.Optional[str]]:
+    def _time_format(self: Generator, expression: exp.UnixToStr | exp.StrToUnix) -> t.Optional[str]:
+        """
+        Returns the time format for a given expression, unless it's equivalent
+        to the default time format of the dialect of interest.
+        """
+        time_format = self.format_time(expression)
+        return time_format if time_format != Dialect.get_or_raise(dialect).TIME_FORMAT else None
+
+    return _time_format
+
+
 def create_with_partitions_sql(self: Generator, expression: exp.Create) -> str:
     """
     In Hive and Spark, the PARTITIONED BY property acts as an extension of a table's schema. When the
@@ -699,3 +717,8 @@ def simplify_literal(expression: E) -> E:
 
 def binary_from_function(expr_type: t.Type[B]) -> t.Callable[[t.List], B]:
     return lambda args: expr_type(this=seq_get(args, 0), expression=seq_get(args, 1))
+
+
+# Used to represent DATE_TRUNC in Doris, Postgres and Starrocks dialects
+def parse_timestamp_trunc(args: t.List) -> exp.TimestampTrunc:
+    return exp.TimestampTrunc(this=seq_get(args, 1), unit=seq_get(args, 0))