From 7e44426452d678af5786856cbd576e88fc2c3c7e Mon Sep 17 00:00:00 2001
From: Sebastiaan de Schaetzen <sebastiaan.de.schaetzen@gmail.com>
Date: Sat, 31 May 2025 10:31:55 +0200
Subject: [PATCH] Add support for scanning columns (#5)

Reviewed-on: https://gitea.seeseepuff.be/seeseemelk/mysqlite/pulls/5
---
 query.go      | 17 +++++++++++++++++
 query_test.go | 13 +++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/query.go b/query.go
index 831f8a3..f0fdedf 100644
--- a/query.go
+++ b/query.go
@@ -119,6 +119,23 @@ func (q *Query) MustExec() {
 	}
 }
 
+func (q *Query) ScanColumns(results *[]string) *Query {
+	if q.err != nil {
+		return q
+	}
+
+	// Ensure the number of results matches the number of columns
+	if q.stmt.ColumnCount() != len(*results) {
+		*results = make([]string, q.stmt.ColumnCount())
+	}
+
+	// Fetch the column names
+	for i := 0; i < q.stmt.ColumnCount(); i++ {
+		(*results)[i] = q.stmt.ColumnName(i)
+	}
+	return q
+}
+
 func (q *Query) ScanSingle(results ...any) (rerr error) {
 	defer q.unlock()
 	// Scan rows
diff --git a/query_test.go b/query_test.go
index baab78c..4a4b409 100644
--- a/query_test.go
+++ b/query_test.go
@@ -35,6 +35,19 @@ func TestScanWithMissingValues(t *testing.T) {
 	require.Equal(t, ErrMissingScan, err)
 }
 
+func TestScanColumns(t *testing.T) {
+	db := openTestDb(t)
+	var columns []string
+	var key string
+	err := db.Query("select `key` from mytable").
+		ScanColumns(&columns).
+		ScanSingle(&key)
+	require.NoError(t, err, "expected no error scanning columns")
+	require.Equal(t, 1, len(columns), "expected one column")
+	require.Equal(t, "key", columns[0], "expected column name 'key'")
+	require.Equal(t, "foo", key, "expected key to be 'foo'")
+}
+
 func TestBindInt64(t *testing.T) {
 	db := openTestDb(t)
 	var value int64