fix: improve column and returning type hints

docs/examples/adbc_example.py

@@ -16,10 +16,10 @@ def adbc_example() -> None:
     # Create SQLSpec instance with ADBC (connects to dev PostgreSQL container)
     spec = SQLSpec()
     config = AdbcConfig(connection_config={"uri": "postgresql://postgres:postgres@localhost:5433/postgres"})
-    spec.add_config(config)
+    db = spec.add_config(config)
 
     # Get a driver directly (drivers now have built-in query methods)
-    with spec.provide_session(config) as driver:
+    with spec.provide_session(db) as driver:
         # Create a table
         driver.execute("""
             CREATE TABLE IF NOT EXISTS analytics_data (

pyproject.toml

@@ -13,7 +13,7 @@ maintainers = [{ name = "Litestar Developers", email = "[email protected]" }]
 name = "sqlspec"
 readme = "README.md"
 requires-python = ">=3.9, <4.0"
-version = "0.17.0"
+version = "0.17.1"
 
 [project.urls]
 Discord = "https://discord.gg/litestar"

sqlspec/builder/_column.py

@@ -5,7 +5,7 @@
 """
 
 from collections.abc import Iterable
-from typing import Any, Optional
+from typing import Any, Optional, cast
 
 from sqlglot import exp
 
@@ -241,6 +241,10 @@ def desc(self) -> exp.Ordered:
         """Create a DESC ordering expression."""
         return exp.Ordered(this=self._expression, desc=True)
 
+    def as_(self, alias: str) -> exp.Alias:
+        """Create an aliased expression."""
+        return cast("exp.Alias", exp.alias_(self._expression, alias))
+
     def __repr__(self) -> str:
         if self.table:
             return f"Column<{self.table}.{self.name}>"

sqlspec/builder/_expression_wrappers.py

@@ -0,0 +1,46 @@
+"""Expression wrapper classes for proper type annotations."""
+
+from typing import cast
+
+from sqlglot import exp
+
+__all__ = ("AggregateExpression", "ConversionExpression", "FunctionExpression", "MathExpression", "StringExpression")
+
+
+class ExpressionWrapper:
+    """Base wrapper for SQLGlot expressions."""
+
+    def __init__(self, expression: exp.Expression) -> None:
+        self._expression = expression
+
+    def as_(self, alias: str) -> exp.Alias:
+        """Create an aliased expression."""
+        return cast("exp.Alias", exp.alias_(self._expression, alias))
+
+    @property
+    def expression(self) -> exp.Expression:
+        """Get the underlying SQLGlot expression."""
+        return self._expression
+
+    def __str__(self) -> str:
+        return str(self._expression)
+
+
+class AggregateExpression(ExpressionWrapper):
+    """Aggregate functions like COUNT, SUM, AVG."""
+
+
+class FunctionExpression(ExpressionWrapper):
+    """General SQL functions."""
+
+
+class MathExpression(ExpressionWrapper):
+    """Mathematical functions like ROUND."""
+
+
+class StringExpression(ExpressionWrapper):
+    """String functions like UPPER, LOWER, LENGTH."""
+
+
+class ConversionExpression(ExpressionWrapper):
+    """Conversion functions like CAST, COALESCE."""

sqlspec/builder/_insert.py

@@ -412,9 +412,7 @@ def do_update(self, **kwargs: Any) -> "Insert":
         # Create ON CONFLICT with proper structure
         conflict_keys = [exp.to_identifier(col) for col in self._columns] if self._columns else None
         on_conflict = exp.OnConflict(
-            conflict_keys=conflict_keys,
-            action=exp.var("DO UPDATE"),
-            expressions=set_expressions if set_expressions else None,
+            conflict_keys=conflict_keys, action=exp.var("DO UPDATE"), expressions=set_expressions or None
         )
 
         insert_expr.set("conflict", on_conflict)

sqlspec/builder/_update.py

@@ -44,26 +44,26 @@ class Update(
         update_query = (
             Update()
             .table("users")
-            .set(name="John Doe")
-            .set(email="[email protected]")
+            .set_(name="John Doe")
+            .set_(email="[email protected]")
             .where("id = 1")
         )
 
         update_query = (
-            Update("users").set(name="John Doe").where("id = 1")
+            Update("users").set_(name="John Doe").where("id = 1")
         )
 
         update_query = (
             Update()
             .table("users")
-            .set(status="active")
+            .set_(status="active")
             .where_eq("id", 123)
         )
 
         update_query = (
             Update()
             .table("users", "u")
-            .set(name="Updated Name")
+            .set_(name="Updated Name")
             .from_("profiles", "p")
             .where("u.id = p.user_id AND p.is_verified = true")
         )

sqlspec/builder/mixins/_order_limit_operations.py

@@ -10,6 +10,9 @@
 from sqlspec.exceptions import SQLBuilderError
 
 if TYPE_CHECKING:
+    from sqlspec.builder._column import Column
+    from sqlspec.builder._expression_wrappers import ExpressionWrapper
+    from sqlspec.builder.mixins._select_operations import Case
     from sqlspec.protocols import SQLBuilderProtocol
 
 __all__ = ("LimitOffsetClauseMixin", "OrderByClauseMixin", "ReturningClauseMixin")
@@ -24,7 +27,7 @@ class OrderByClauseMixin:
     # Type annotation for PyRight - this will be provided by the base class
     _expression: Optional[exp.Expression]
 
-    def order_by(self, *items: Union[str, exp.Ordered], desc: bool = False) -> Self:
+    def order_by(self, *items: Union[str, exp.Ordered, "Column"], desc: bool = False) -> Self:
         """Add ORDER BY clause.
 
         Args:
@@ -49,7 +52,13 @@ def order_by(self, *items: Union[str, exp.Ordered], desc: bool = False) -> Self:
                 if desc:
                     order_item = order_item.desc()
             else:
-                order_item = item
+                # Extract expression from Column objects or use as-is for sqlglot expressions
+                from sqlspec._sql import SQLFactory
+
+                extracted_item = SQLFactory._extract_expression(item)
+                order_item = extracted_item
+                if desc and not isinstance(item, exp.Ordered):
+                    order_item = order_item.desc()
             current_expr = current_expr.order_by(order_item, copy=False)
         builder._expression = current_expr
         return cast("Self", builder)
@@ -111,7 +120,7 @@ class ReturningClauseMixin:
     # Type annotation for PyRight - this will be provided by the base class
     _expression: Optional[exp.Expression]
 
-    def returning(self, *columns: Union[str, exp.Expression]) -> Self:
+    def returning(self, *columns: Union[str, exp.Expression, "Column", "ExpressionWrapper", "Case"]) -> Self:
         """Add RETURNING clause to the statement.
 
         Args:
@@ -130,6 +139,9 @@ def returning(self, *columns: Union[str, exp.Expression]) -> Self:
         if not isinstance(self._expression, valid_types):
             msg = "RETURNING is only supported for INSERT, UPDATE, and DELETE statements."
             raise SQLBuilderError(msg)
-        returning_exprs = [exp.column(c) if isinstance(c, str) else c for c in columns]
+        # Extract expressions from various wrapper types
+        from sqlspec._sql import SQLFactory
+
+        returning_exprs = [SQLFactory._extract_expression(c) for c in columns]
         self._expression.set("returning", exp.Returning(expressions=returning_exprs))
         return self

sqlspec/builder/mixins/_select_operations.py

@@ -858,7 +858,7 @@ def when(self, condition: Union[str, exp.Expression], value: Union[str, exp.Expr
         from sqlspec._sql import SQLFactory
 
         cond_expr = exp.maybe_parse(condition) or exp.column(condition) if isinstance(condition, str) else condition
-        val_expr = SQLFactory._to_literal(value)
+        val_expr = SQLFactory._to_expression(value)
 
         # SQLGlot uses exp.If for CASE WHEN clauses, not exp.When
         when_clause = exp.If(this=cond_expr, true=val_expr)
@@ -876,7 +876,7 @@ def else_(self, value: Union[str, exp.Expression, Any]) -> Self:
         """
         from sqlspec._sql import SQLFactory
 
-        self._default = SQLFactory._to_literal(value)
+        self._default = SQLFactory._to_expression(value)
         return self
 
     def end(self) -> Self:

sqlspec/builder/mixins/_update_operations.py

@@ -111,10 +111,10 @@ def set(self, *args: Any, **kwargs: Any) -> Self:
         """Set columns and values for the UPDATE statement.
 
         Supports:
-        - set(column, value)
-        - set(mapping)
-        - set(**kwargs)
-        - set(mapping, **kwargs)
+        - set_(column, value)
+        - set_(mapping)
+        - set_(**kwargs)
+        - set_(mapping, **kwargs)
 
         Args:
             *args: Either (column, value) or a mapping.

sqlspec/protocols.py

@@ -20,6 +20,7 @@
 __all__ = (
     "BytesConvertibleProtocol",
     "DictProtocol",
+    "ExpressionWithAliasProtocol",
     "FilterAppenderProtocol",
     "FilterParameterProtocol",
     "HasExpressionProtocol",
@@ -172,6 +173,15 @@ def __bytes__(self) -> bytes:
         ...
 
 
+@runtime_checkable
+class ExpressionWithAliasProtocol(Protocol):
+    """Protocol for SQL expressions that support aliasing with as_() method."""
+
+    def as_(self, alias: str, **kwargs: Any) -> "exp.Alias":
+        """Create an aliased expression."""
+        ...
+
+
 @runtime_checkable
 class ObjectStoreItemProtocol(Protocol):
     """Protocol for object store items with path/key attributes."""

tests/unit/test_builder/test_parameter_naming.py

@@ -13,6 +13,8 @@
 - Edge cases and error conditions
 """
 
+import string
+
 from sqlspec import sql
 
 
@@ -329,7 +331,7 @@ def test_parameter_names_are_sql_safe() -> None:
         assert "--" not in param_name
 
         # Should be valid identifier-like
-        assert param_name.replace("_", "").replace("0123456789", "").isalpha() or "_" in param_name
+        assert param_name.replace("_", "").replace(string.digits, "").isalpha() or "_" in param_name
 
 
 def test_empty_and_null_values_preserve_column_names() -> None:

tests/unit/test_sql_factory.py

@@ -416,35 +416,63 @@ def test_all_ddl_methods_exist() -> None:
 
 def test_count_function() -> None:
     """Test sql.count() function."""
+    from sqlspec.builder._expression_wrappers import AggregateExpression
+
     expr = sql.count()
-    assert isinstance(expr, exp.Expression)
+    assert isinstance(expr, AggregateExpression)
+    assert hasattr(expr, "as_")
+    assert hasattr(expr, "expression")
+    assert isinstance(expr.expression, exp.Expression)
 
     count_column = sql.count("user_id")
-    assert isinstance(count_column, exp.Expression)
+    assert isinstance(count_column, AggregateExpression)
+    assert hasattr(count_column, "as_")
+    assert hasattr(count_column, "expression")
+    assert isinstance(count_column.expression, exp.Expression)
 
 
 def test_sum_function() -> None:
     """Test sql.sum() function."""
+    from sqlspec.builder._expression_wrappers import AggregateExpression
+
     expr = sql.sum("amount")
-    assert isinstance(expr, exp.Expression)
+    assert isinstance(expr, AggregateExpression)
+    assert hasattr(expr, "as_")
+    assert hasattr(expr, "expression")
+    assert isinstance(expr.expression, exp.Expression)
 
 
 def test_avg_function() -> None:
     """Test sql.avg() function."""
+    from sqlspec.builder._expression_wrappers import AggregateExpression
+
     expr = sql.avg("score")
-    assert isinstance(expr, exp.Expression)
+    assert isinstance(expr, AggregateExpression)
+    assert hasattr(expr, "as_")
+    assert hasattr(expr, "expression")
+    assert isinstance(expr.expression, exp.Expression)
 
 
 def test_max_function() -> None:
     """Test sql.max() function."""
+    from sqlspec.builder._expression_wrappers import AggregateExpression
+
     expr = sql.max("created_at")
-    assert isinstance(expr, exp.Expression)
+    assert isinstance(expr, AggregateExpression)
+    assert hasattr(expr, "as_")
+    assert hasattr(expr, "expression")
+    assert isinstance(expr.expression, exp.Expression)
 
 
 def test_min_function() -> None:
     """Test sql.min() function."""
+    from sqlspec.builder._expression_wrappers import AggregateExpression
+
     expr = sql.min("price")
-    assert isinstance(expr, exp.Expression)
+    assert isinstance(expr, AggregateExpression)
+    assert hasattr(expr, "as_")
+    assert hasattr(expr, "expression")
+    assert isinstance(expr.expression, exp.Expression)
 
 
 def test_column_method() -> None:
@@ -1074,7 +1102,7 @@ def test_type_compatibility_across_all_operations() -> None:
 
 
 def test_update_set_method_with_sql_objects() -> None:
-    """Test that UPDATE.set() method properly handles SQL objects with kwargs."""
+    """Test that UPDATE.set_() method properly handles SQL objects with kwargs."""
     raw_timestamp = sql.raw("NOW()")
     raw_computed = sql.raw("UPPER(:value)", value="test")
 
@@ -1097,7 +1125,7 @@ def test_update_set_method_with_sql_objects() -> None:
 
 
 def test_update_set_method_backward_compatibility() -> None:
-    """Test that UPDATE.set() method maintains backward compatibility with dict."""
+    """Test that UPDATE.set_() method maintains backward compatibility with dict."""
     raw_timestamp = sql.raw("NOW()")
 
     # Test using dict (original API)