func (this *JSConverter) VisitIsNull(expr *expression.IsNull) (interface{}, error) {
var buf bytes.Buffer
buf.WriteString("(")
buf.WriteString(this.Visit(expr.Operand()))
buf.WriteString(" == null)")
return buf.String(), nil
}
func newSargNull(pred *expression.IsNull) *sargNull {
rv := &sargNull{}
rv.sarger = func(expr2 expression.Expression) (plan.Spans, error) {
if SubsetOf(pred, expr2) {
return _SELF_SPANS, nil
}
if pred.Operand().EquivalentTo(expr2) {
return _NULL_SPANS, nil
}
return nil, nil
}
return rv
}
