Fix select statement detection when used in parenthesis (#197)

Author: yfuruyama

statement.go

@@ -84,8 +84,10 @@ type QueryStats struct {
 }
 
 var (
-	// SQL
-	selectRe = regexp.MustCompile(`(?is)^(?:WITH|CALL|@{.+|SELECT|GRAPH)\s.+$`)
+	// Query
+	selectRe = regexp.MustCompile(`(?is)^(@{[^}]+}\s*)?(\(\s*)?(?:WITH|SELECT)\s.+$`)
+	graphRe  = regexp.MustCompile(`(?is)^GRAPH\s.+$`)
+	callRe   = regexp.MustCompile(`(?is)^CALL\s.+$`)
 
 	// DDL
 	createDatabaseRe = regexp.MustCompile(`(?is)^CREATE\s+DATABASE\s.+$`)
@@ -143,7 +145,7 @@ func BuildStatementWithComments(stripped, raw string) (Statement, error) {
 	case useRe.MatchString(stripped):
 		matched := useRe.FindStringSubmatch(stripped)
 		return &UseStatement{Database: unquoteIdentifier(matched[1]), Role: unquoteIdentifier(matched[2])}, nil
-	case selectRe.MatchString(stripped):
+	case selectRe.MatchString(stripped), graphRe.MatchString(stripped), callRe.MatchString(stripped):
 		return &SelectStatement{Query: raw}, nil
 	case createDatabaseRe.MatchString(stripped):
 		return &CreateDatabaseStatement{CreateStatement: stripped}, nil

statement_test.go

@@ -66,6 +66,21 @@ func TestBuildStatement(t *testing.T) {
 			input: "@{USE_ADDITIONAL_PARALLELISM=TRUE} SELECT * FROM t1",
 			want:  &SelectStatement{Query: "@{USE_ADDITIONAL_PARALLELISM=TRUE} SELECT * FROM t1"},
 		},
+		{
+			desc:  "SELECT statement in parenthesis",
+			input: "(SELECT * FROM t1)",
+			want:  &SelectStatement{Query: "(SELECT * FROM t1)"},
+		},
+		{
+			desc:  "WITH statement in parenthesis",
+			input: "(WITH sub AS (SELECT 1) SELECT * FROM sub)",
+			want:  &SelectStatement{Query: "(WITH sub AS (SELECT 1) SELECT * FROM sub)"},
+		},
+		{
+			desc:  "SELECT statement in parenthesis with statement hint",
+			input: "@{USE_ADDITIONAL_PARALLELISM=TRUE} (SELECT * FROM t1)",
+			want:  &SelectStatement{Query: "@{USE_ADDITIONAL_PARALLELISM=TRUE} (SELECT * FROM t1)"},
+		},
 		{
 			desc:  "CREATE DATABASE statement",
 			input: "CREATE DATABASE d1",