/// <inheritdoc/>
protected override SqlProvider VisitExcept(ExceptProvider provider)
{
var left = Compile(provider.Left);
var right = Compile(provider.Right);
var leftSelect = left.Request.Statement;
var keepOrderForLeft = (leftSelect.HasLimit || leftSelect.HasOffset) && providerInfo.Supports(ProviderFeatures.PagingRequiresOrderBy);
if (!keepOrderForLeft)
{
leftSelect.OrderBy.Clear();
}
var rightSelect = right.Request.Statement;
var keepOrderForRight = (leftSelect.HasLimit || leftSelect.HasOffset) && providerInfo.Supports(ProviderFeatures.PagingRequiresOrderBy);
if (!keepOrderForRight)
{
rightSelect.OrderBy.Clear();
}
var result = SqlDml.Except(leftSelect, rightSelect);
var queryRef = SqlDml.QueryRef(result);
SqlSelect query = SqlDml.Select(queryRef);
query.Columns.AddRange(queryRef.Columns.Cast <SqlColumn>());
return(CreateProvider(query, provider, left, right));
}
protected override Provider VisitExcept(ExceptProvider provider)
{
CompilableProvider left;
CompilableProvider right;
VisitBinaryProvider(provider, out left, out right);
if (left != provider.Left || right != provider.Right)
{
return(new ExceptProvider(left, right));
}
return(provider);
}
protected override Provider VisitExcept(ExceptProvider provider)
{
return(VisitSetOperationProvider(provider));
}
/// <summary> /// Compiles <see cref="ExceptProvider"/>. /// </summary> /// <param name="provider">Except provider.</param> protected abstract TResult VisitExcept(ExceptProvider provider);
protected override Provider VisitExcept(ExceptProvider provider) => VisitSetOperationProvider(provider);
