Failed to assert PGX error using PGconn and PGX - postgresql

Question

rows, err:= b.DB.ExecContext(
ctx,
fmt.Sprintf(`
UPDATE service_slots
SET slots_left = slots_left - %d
WHERE date = $1 AND
start_hour = $2 AND
service_id =$3
`, serviceSlots.Qty),
booking.Date,
booking.Appointment,
serviceSlots.ID,
)
if err!= nil {
var pgErr *pgconn.PgError
if errors.As(err, &pgErr) {
fmt.Println(pgErr.Message) // => syntax error at end of input
fmt.Println(pgErr.Code) // => 42601
}
return err
}
tried to use error assert from pgconn, but somehow cannot make the error get inside errors.As(err,&pgErr)
if I hit the constraint error or any error from postgres, it just pass the errors.As (did not trigger the printline ) and return the normal error.
what is wrong with my code ?
used
github.com/jackc/pgx v3.6.2+incompatible
github.com/jackc/pgconn v1.13.0 // indirect
the error is
"ERROR: new row for relation \"service_slots\" violates check constraint \"slot_nonnegative\" (SQLSTATE 23514)"
-----------SOLVED----------
should not use *pgconn.PgError but should use pgx.PgError instead
thanks to #Adrian for pointing out that I assume the type wrong