Allow fractional days

Author: treysp

sqlglot/expressions.py

@@ -8562,8 +8562,10 @@ def parse_identifier(name: str | Identifier, dialect: DialectType = None) -> Ide
 INTERVAL_STRING_RE = re.compile(r"\s*(-?[0-9]+(?:\.[0-9]+)?)\s*([a-zA-Z]+)\s*")
 
 # Matches day-time interval strings that contain a number of days, a space,
-# and a time component in the format hh:[mm:[ss[.ff]]]
-INTERVAL_DAY_TIME_RE = re.compile(r"^\s*(-?[0-9]+)\s+(\d{1,2}:\d{0,2}(?::\d{0,2}(?:\.\d+)?)?)\s*$")
+# and a time in hh:[mm:[ss[.ff]]] format
+INTERVAL_DAY_TIME_RE = re.compile(
+    r"\s*(-?[0-9]+(?:\.\d+)?)\s+(\d{1,2}:\d{0,2}(?::\d{0,2}(?:\.\d+)?)?)\s*"
+)
 
 
 def to_interval(interval: str | Literal) -> Interval:

sqlglot/generator.py

@@ -3284,7 +3284,7 @@ def interval_sql(self, expression: exp.Interval) -> str:
         if self.SINGLE_STRING_INTERVAL:
             this = expression.this.name if expression.this else ""
             if this:
-                if unit and isinstance(unit_expression, exp.IntervalSpan):
+                if unit_expression and isinstance(unit_expression, exp.IntervalSpan):
                     return f"INTERVAL '{this}'{unit}"
                 return f"INTERVAL '{this}{unit}'"
             return f"INTERVAL{unit}"

sqlglot/parser.py

@@ -5109,17 +5109,18 @@ def _parse_interval(self, match_interval: bool = True) -> t.Optional[exp.Add | e
             self._retreat(index)
             return None
 
-        # detect day-time interval span with omitted units:
-        #   INTERVAL '<days> <time with colon>' [maybe explicit span `unit TO unit`]
+        # handle day-time format interval span with omitted units:
+        #   INTERVAL '<number days> hh:[:mm[:ss[.ff]]]' <maybe `unit TO unit`>
+        day_time_literal = None
         infer_interval_span_units = False
         if (
             this
             and this.is_string
             and self.INTERVAL_SPANS
             and self.SUPPORTS_OMITTED_INTERVAL_SPAN_UNIT
         ):
-            day_time_format_literal = exp.INTERVAL_DAY_TIME_RE.match(this.name)
-            if day_time_format_literal:
+            day_time_literal = exp.INTERVAL_DAY_TIME_RE.match(this.name)
+            if day_time_literal:
                 index = self._index
 
                 # Var "TO" Var
@@ -5128,9 +5129,10 @@ def _parse_interval(self, match_interval: bool = True) -> t.Optional[exp.Add | e
                 if first_unit and self._match_text_seq("TO"):
                     second_unit = self._parse_var(any_token=True, upper=True)
 
-                self._retreat(index)
                 infer_interval_span_units = not (first_unit and second_unit)
 
+                self._retreat(index)
+
         unit = (
             None
             if infer_interval_span_units
@@ -5158,21 +5160,17 @@ def _parse_interval(self, match_interval: bool = True) -> t.Optional[exp.Add | e
                 this = exp.Literal.string(parts[0][0])
                 unit = self.expression(exp.Var, this=parts[0][1].upper())
 
-            # infer DAY TO MINUTE/SECOND omitted span units
-            if (
-                self.INTERVAL_SPANS
-                and self.SUPPORTS_OMITTED_INTERVAL_SPAN_UNIT
-                and day_time_format_literal
-            ):
-                time_part = day_time_format_literal.group(2)
-
-                if infer_interval_span_units:
+            if infer_interval_span_units and day_time_literal:
+                time_part = day_time_literal.group(2)
+                if time_part:
+                    # two colons for 'hh:mm:[ss[.ff]]', period for 'mm:ss.ff'
                     seconds_present = time_part.count(":") >= 2 or "." in time_part
                     unit = self.expression(
                         exp.IntervalSpan,
                         this=exp.var("DAY"),
                         expression=exp.var("SECOND" if seconds_present else "MINUTE"),
                     )
+
         if (
             self.INTERVAL_SPANS
             and self._match_text_seq("TO")

tests/dialects/test_postgres.py

@@ -1639,12 +1639,19 @@ def test_begin_transaction(self):
                     ).assert_is(exp.Transaction)
 
     def test_interval_span(self):
-        for time_str in ["1 01:", "1 01:", "1 01:00", "1 01:00"]:
+        for time_str in ["1 01:", "1 01:00", "1.5 01:", "-0.25 01:"]:
             self.validate_identity(f"INTERVAL '{time_str}'", f"INTERVAL '{time_str}' DAY TO MINUTE")
             # explicit SECOND overrides inference to MINUTE
             self.validate_identity(f"INTERVAL '{time_str}' DAY TO SECOND")
 
-        for time_str in ["1 01:01:", "1 01:01:", "1 01:01:01", "1 01:01:01.01"]:
+        for time_str in [
+            "1 01:01:",
+            "1 01:01:",
+            "1 01:01:01",
+            "1 01:01:01.01",
+            "1.5 01:01:",
+            "-0.25 01:01:",
+        ]:
             self.validate_identity(f"INTERVAL '{time_str}'", f"INTERVAL '{time_str}' DAY TO SECOND")
             # explicit MINUTE overrides inference to SECOND
             self.validate_identity(f"INTERVAL '{time_str}' DAY TO MINUTE")