fix: check if column can be from a left or right joined table

parser/src/nullable.rs

@@ -27,6 +27,10 @@ pub fn is_column_nullable(
 			..
 		} = select.body.select
 	{
+		if is_table_name_in_left_or_right_join(table_name, &from) {
+			return None;
+		}
+
 		// If a column is declared as not null we only need to prove that the table it came from is always present
 		if notnull {
 			return get_used_table_name(table_name, &from).map(|_| NullableResult::NotNull);
@@ -61,6 +65,25 @@ pub fn is_column_nullable(
 	None
 }
 
+fn is_table_name_in_left_or_right_join(table_name: &str, from: &ast::FromClause) -> bool {
+	if let Some(joins) = &from.joins {
+		for join in joins {
+			if let ast::JoinedSelectTable {
+				operator: ast::JoinOperator::TypedJoin(Some(join_type)),
+				table: ast::SelectTable::Table(name, _, _),
+				..
+			} = join && (*join_type == (ast::JoinType::LEFT | ast::JoinType::OUTER)
+				|| *join_type == (ast::JoinType::RIGHT | ast::JoinType::OUTER))
+				&& compare_identifier(&name.name.0, table_name)
+			{
+				return true;
+			}
+		}
+	}
+
+	false
+}
+
 fn get_used_table_name<'a>(table_name: &str, from: &'a ast::FromClause) -> Option<&'a str> {
 	if let Some(table) = &from.select {
 		match table.as_ref() {
@@ -532,5 +555,25 @@ mod tests {
 			is_column_nullable("id", "bar", true, "select * from foo left join bar"),
 			None
 		);
+		assert_eq!(
+			is_column_nullable("id", "foo", true, "select * from foo left join bar"),
+			Some(NullableResult::NotNull)
+		);
+		assert_eq!(
+			is_column_nullable("id", "foo", true, "select * from foo left join foo"),
+			None
+		);
+		assert_eq!(
+			is_column_nullable("id", "bar", true, "select * from foo right join bar"),
+			None
+		);
+		assert_eq!(
+			is_column_nullable("id", "foo", true, "select * from foo right join bar"),
+			Some(NullableResult::NotNull)
+		);
+		assert_eq!(
+			is_column_nullable("id", "foo", true, "select * from foo right join foo"),
+			None
+		);
 	}
 }