protected override Expression VisitSubQuery(SubQueryExpression expression)
{
var subQueryModel = expression.QueryModel;
var contains = subQueryModel.ResultOperators.FirstOrDefault() as ContainsResultOperator;
// Check if IEnumerable.Contains is used.
if (subQueryModel.ResultOperators.Count == 1 && contains != null)
{
VisitContains(subQueryModel, contains);
}
else if (_visitEntireSubQueryModel)
{
ResultBuilder.Append('(');
_modelVisitor.VisitQueryModel(subQueryModel, false, true);
ResultBuilder.Append(')');
}
else
{
// This happens when New expression uses a subquery, in a GroupBy.
_modelVisitor.VisitSelectors(expression.QueryModel, false);
}
return(expression);
}
/// <summary>
/// Visits IEnumerable.Contains
/// </summary>
private void VisitContains(QueryModel subQueryModel, ContainsResultOperator contains)
{
ResultBuilder.Append("(");
var fromExpression = subQueryModel.MainFromClause.FromExpression;
var queryable = ExpressionWalker.GetCacheQueryable(fromExpression, false);
if (queryable != null)
{
Visit(contains.Item);
ResultBuilder.Append(" IN (");
_modelVisitor.VisitQueryModel(subQueryModel);
ResultBuilder.Append(")");
}
else
{
var inValues = GetInValues(fromExpression).ToArray();
var hasNulls = inValues.Any(o => o == null);
if (hasNulls)
{
ResultBuilder.Append("(");
}
Visit(contains.Item);
ResultBuilder.Append(" IN (");
AppendInParameters(inValues);
ResultBuilder.Append(")");
if (hasNulls)
{
ResultBuilder.Append(") OR ");
Visit(contains.Item);
ResultBuilder.Append(" IS NULL");
}
}
ResultBuilder.Append(")");
}
