jackc/pgx · error

cannot scan NULL into *string

Error message

cannot scan NULL into *string

What it means

Returned by stringWrapper.ScanText when the PostgreSQL text value is NULL (Valid==false). A plain Go string has no NULL representation, so the scan refuses rather than storing an empty string that would be indistinguishable from ''.

Solutions

1. Use COALESCE(col, '') in the query when empty string is an acceptable default
2. Scan into pgtype.Text or *string to preserve NULL semantics
3. Declare the column NOT NULL

When it happens

Trigger: Thrown at pgtype/builtin_wrappers.go:387 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of jackc/pgx@ec1a0befd2 (2026-08-04). Data as JSON: /api/errors/887a5d461e07af38. Report an issue: GitHub.

Appendix: source

Thrown at pgtype/builtin_wrappers.go:387

		return fmt.Errorf("cannot scan NULL into *float64")
	}

	*w = float64Wrapper(v.Float64)

	return nil
}

func (w float64Wrapper) Float64Value() (Float8, error) {
	return Float8{Float64: float64(w), Valid: true}, nil
}

type stringWrapper string

func (w stringWrapper) SkipUnderlyingTypePlan() {}

func (w *stringWrapper) ScanText(v Text) error {
	if !v.Valid {
		return fmt.Errorf("cannot scan NULL into *string")
	}

	*w = stringWrapper(v.String)
	return nil
}

func (w stringWrapper) TextValue() (Text, error) {
	return Text{String: string(w), Valid: true}, nil
}

type timeWrapper time.Time

func (w *timeWrapper) ScanDate(v Date) error {
	if !v.Valid {
		return fmt.Errorf("cannot scan NULL into *time.Time")
	}

	switch v.InfinityModifier {

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