Add support for try expressions

Author: renaudb

_duckdb-stubs/__init__.pyi

@@ -884,6 +884,7 @@ class Expression:
     def otherwise(self, value: Expression) -> Expression: ...
     def show(self) -> None: ...
     def when(self, condition: Expression, value: Expression) -> Expression: ...
+    def try_(self, condition: Expression, value: Expression) -> Expression: ...
 
 class FatalException(DatabaseError): ...
 

src/duckdb_py/include/duckdb_python/expression/pyexpression.hpp

@@ -83,6 +83,10 @@ struct DuckDBPyExpression : public enable_shared_from_this<DuckDBPyExpression> {
 	shared_ptr<DuckDBPyExpression> In(const py::args &args);
 	shared_ptr<DuckDBPyExpression> NotIn(const py::args &args);
 
+	// TRY
+
+	shared_ptr<DuckDBPyExpression> Try();
+
 	// Order modifiers
 
 	shared_ptr<DuckDBPyExpression> Ascending();

src/duckdb_py/pyexpression.cpp

@@ -226,6 +226,12 @@ shared_ptr<DuckDBPyExpression> DuckDBPyExpression::NotIn(const py::args &args) {
 	return CreateCompareExpression(ExpressionType::COMPARE_NOT_IN, args);
 }
 
+// TRY
+
+shared_ptr<DuckDBPyExpression> DuckDBPyExpression::Try() {
+	return DuckDBPyExpression::InternalUnaryOperator(ExpressionType::OPERATOR_TRY, *this);
+}
+
 // COALESCE
 
 shared_ptr<DuckDBPyExpression> DuckDBPyExpression::Coalesce(const py::args &args) {

src/duckdb_py/pyexpression/initialize.cpp

@@ -367,6 +367,14 @@ void DuckDBPyExpression::Initialize(py::module_ &m) {
 	)";
 	expression.def("isnotin", &DuckDBPyExpression::NotIn, docs);
 
+	docs = R"(
+		Create a TRY expression from self
+
+		Returns:
+			DuckDBPyExpression: TRY(self)
+	)";
+	expression.def("try_", &DuckDBPyExpression::Try, docs);
+
 	docs = R"(
 		Return the stringified version of the expression.
 

tests/fast/test_expression.py

@@ -928,6 +928,24 @@ def test_null(self):
         res2 = rel.filter(b.isnotnull()).fetchall()
         assert res2 == [(1, "a"), (2, "b"), (4, "c"), (5, "a")]
 
+    def test_try(self):
+        con = duckdb.connect()
+        rel = con.sql(
+            """
+            select * from (VALUES
+                (-1.0),
+                (0.0),
+                (1.0),
+                (NULL),
+            ) tbl(a)
+        """
+        )
+
+        expr = FunctionExpression("sqrt", ColumnExpression("a"))
+
+        res = rel.select(expr.try_()).fetchall()
+        assert res == [(None,), (0.0,), (1.0,), (None,)]
+
     def test_sort(self):
         con = duckdb.connect()
         rel = con.sql(