Fix: interval execution closes #1650

sqlglot/executor/env.py

@@ -5,6 +5,7 @@
 from functools import wraps
 
 from sqlglot import exp
+from sqlglot.generator import Generator
 from sqlglot.helper import PYTHON_VERSION
 
 
@@ -119,9 +120,11 @@ def ordered(this, desc, nulls_first):
 
 @null_if_any
 def interval(this, unit):
-    if unit == "DAY":
-        return datetime.timedelta(days=float(this))
-    raise NotImplementedError
+    unit = unit.lower()
+    plural = unit + "s"
+    if plural in Generator.TIME_PART_SINGULARS:
+        unit = plural
+    return datetime.timedelta(**{unit: float(this)})
 
 
 ENV = {

sqlglot/executor/python.py

@@ -413,6 +413,7 @@ class Generator(generator.Generator):
             exp.Distinct: lambda self, e: f"set({self.sql(e, 'this')})",
             exp.Extract: lambda self, e: f"EXTRACT('{e.name.lower()}', {self.sql(e, 'expression')})",
             exp.In: lambda self, e: f"{self.sql(e, 'this')} in ({self.expressions(e, flat=True)})",
+            exp.Interval: lambda self, e: f"INTERVAL({self.sql(e.this)}, '{self.sql(e.unit)}')",
             exp.Is: lambda self, e: self.binary(e, "is"),
             exp.Lambda: _lambda_sql,
             exp.Not: lambda self, e: f"not {self.sql(e.this)}",

sqlglot/expressions.py

@@ -3509,6 +3509,10 @@ def __init__(self, **args):
 class Interval(TimeUnit):
     arg_types = {"this": False, "unit": False}
 
+    @property
+    def unit(self) -> t.Optional[Var]:
+        return self.args.get("unit")
+
 
 class IgnoreNulls(Expression):
     pass

tests/test_executor.py

@@ -566,6 +566,7 @@ def test_scalar_functions(self):
             ("IF(false, 1, 0)", 0),
             ("CASE WHEN 0 = 1 THEN 'foo' ELSE 'bar' END", "bar"),
             ("CAST('2022-01-01' AS DATE) + INTERVAL '1' DAY", date(2022, 1, 2)),
+            ("INTERVAL '1' week", datetime.timedelta(weeks=1)),
             ("1 IN (1, 2, 3)", True),
             ("1 IN (2, 3)", False),
             ("NULL IS NULL", True),