Add support for scanning columns (#5)

Reviewed-on: #5

errors.go

@@ -4,3 +4,4 @@ import "errors"
 
 var ErrNoRows = errors.New("mysqlite: no rows returned")
 var ErrMissingBind = errors.New("mysqlite: missing bind value")
+var ErrMissingScan = errors.New("mysqlite: missing scan value")

query.go

@@ -66,6 +66,9 @@ func (q *Query) bindInto(into *int, args ...any) *Query {
 		} else if asInt, ok := arg.(int); ok {
 			q.stmt.BindInt64(*into, int64(asInt))
 			q.binds++
+		} else if asInt64, ok := arg.(int64); ok {
+			q.stmt.BindInt64(*into, asInt64)
+			q.binds++
 		} else if asFloat, ok := arg.(float64); ok {
 			q.stmt.BindFloat(*into, asFloat)
 			q.binds++
@@ -116,6 +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
@@ -215,6 +235,9 @@ func (r *Rows) MustNext() bool {
 }
 
 func (r *Rows) Scan(results ...any) error {
+	if r.query.stmt.ColumnCount() != len(results) {
+		return ErrMissingScan
+	}
 	for i, arg := range results {
 		err := r.scanArgument(i, arg)
 		if err != nil {

query_test.go

@@ -28,6 +28,36 @@ func TestSimpleQueryWithNoResults(t *testing.T) {
 	require.True(t, errors.Is(err, ErrNoRows))
 }
 
+func TestScanWithMissingValues(t *testing.T) {
+	db := openTestDb(t)
+	var count int
+	err := db.Query("select 1, 2").ScanSingle(&count)
+	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
+	var result int64
+	value = 5
+	err := db.Query("select ?").Bind(&value).ScanSingle(&result)
+	require.NoError(t, err)
+	require.Equal(t, int64(5), result)
+}
+
 func TestSimpleQueryWithArgs(t *testing.T) {
 	db := openTestDb(t)
 	var value string