feat: parse IsDistinct

q/parse.go

@@ -136,6 +136,11 @@ func findQueryType(p *parser) (string, error) {
 func parseSelectStatement(p *parser) error {
 	selectQuery := p.query.(*Select)
 
+	distinctErr := parseDistinct(p)
+	if distinctErr != nil {
+		return distinctErr
+	}
+
 	foundWildcard, _ := p.findToken(func(t Token) bool {
 		return t.Type == sqllexer.WILDCARD
 	})
@@ -170,6 +175,20 @@ func parseSelectStatement(p *parser) error {
 	return nil
 }
 
+func parseDistinct(p *parser) error {
+	selectQuery := p.query.(*Select)
+
+	foundDistinctKeyword, _ := p.findToken(func(t Token) bool {
+		return t.Type == sqllexer.KEYWORD && strings.ToUpper(t.Value) == "DISTINCT"
+	})
+
+	if foundDistinctKeyword != nil {
+		selectQuery.IsDistinct = true
+	}
+
+	return nil
+}
+
 func parseSelectColumns(p *parser) error {
 	selectQuery := p.query.(*Select)
 

q/parse_test.go

@@ -43,6 +43,23 @@ func TestParseSelectStatement_StateMachine(t *testing.T) {
 				},
 			},
 		},
+		{
+			input: "SELECT DISTINCT username, email FROM users",
+			expected: &Select{
+				Type:       SELECT,
+				IsDistinct: true,
+				Table:      Table{Name: "users"},
+				IsWildcard: false,
+				Columns: []Column{
+					{
+						Name: "username",
+					},
+					{
+						Name: "email",
+					},
+				},
+			},
+		},
 		{
 			input: "SELECT CustomerName AS Customer, City AS town FROM Customers AS People",
 			expected: &Select{
@@ -229,6 +246,9 @@ func TestParseSelectStatement_StateMachine(t *testing.T) {
 			if answerAsSelect.Table.Alias != expected.Table.Alias {
 				t.Errorf("got %s for Select.Table.Alias, expected %s", answerAsSelect.Table.Alias, expected.Table.Alias)
 			}
+			if answerAsSelect.IsDistinct != expected.IsDistinct {
+				t.Errorf("got %v for Select.IsDistinct, expected %v", answerAsSelect.IsDistinct, expected.IsDistinct)
+			}
 
 			if len(answerAsSelect.Columns) != len(expected.Columns) {
 				t.Errorf("got %d number of columns for Select.Columns, expected %d", len(answerAsSelect.Columns), len(expected.Columns))