protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
if (select.Skip != null)
{
SelectExpression newSelect = select.SetSkip(null).SetTake(null);
bool canAddColumn = !select.IsDistinct && (select.GroupBy == null || select.GroupBy.Count == 0);
if (!canAddColumn)
{
newSelect = newSelect.AddRedundantSelect(new TableAlias());
}
var colType = DbTypeSystem.GetColumnType(typeof(int));
newSelect = newSelect.AddColumn(new ColumnDeclaration(columnName, new RowNumberExpression(select.OrderBy), colType));
// add layer for WHERE clause that references new rownum column
newSelect = newSelect.AddRedundantSelect(new TableAlias());
newSelect = newSelect.RemoveColumn(newSelect.Columns.Single(c => c.Name == columnName));
var newAlias = ((SelectExpression)newSelect.From).Alias;
ColumnExpression rnCol = new ColumnExpression(typeof(int), colType, newAlias, columnName);
Expression where;
if (select.Take != null)
{
where = new BetweenExpression(
rnCol, Expression.Add(select.Skip, Expression.Constant(1)), Expression.Add(select.Skip, select.Take));
}
else
{
where = rnCol.GreaterThan(select.Skip);
}
if (newSelect.Where != null)
{
where = newSelect.Where.And(where);
}
newSelect = newSelect.SetWhere(where);
select = newSelect;
}
return select;
}
protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
if (select.Skip != null)
{
var newSelect = select.SetSkip(null).SetTake(null).AddRedundantSelect(_language, new TableAlias());
_hasRowNumberExpression = true;
var colType = _language.TypeSystem.GetColumnType(typeof(int));
newSelect = newSelect.AddColumn(new ColumnDeclaration("rownum", new RowNumberExpression(select.OrderBy), colType));
// add layer for WHERE clause that references new rownum column
newSelect = newSelect.AddRedundantSelect(_language, new TableAlias());
newSelect = newSelect.RemoveColumn(newSelect.Columns.Single(c => c.Name == "rownum"));
var newAlias = ((SelectExpression)newSelect.From).Alias;
var rowNumberColumn = new ColumnExpression(typeof(int), colType, newAlias, "rownum");
Expression where;
if (select.Take != null)
{
where = new BetweenExpression(rowNumberColumn, Expression.Add(select.Skip, Expression.Constant(1)), Expression.Add(select.Skip, select.Take));
}
else
{
where = rowNumberColumn.GreaterThan(select.Skip);
}
if (newSelect.Where != null)
{
where = newSelect.Where.And(where);
}
newSelect = newSelect.SetWhere(where);
select = newSelect;
}
return(select);
}
protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
if (select.Skip != null)
{
SelectExpression newSelect = select.SetSkip(null).SetTake(null);
bool canAddColumn = !select.IsDistinct && (select.GroupBy == null || select.GroupBy.Count == 0);
if (!canAddColumn)
{
newSelect = newSelect.AddRedundantSelect(new TableAlias());
}
newSelect = newSelect.AddColumn(new ColumnDeclaration(COLUMN_NAME, new RowNumberExpression(select.OrderBy)));
// add layer for WHERE clause that references new rownum column
newSelect = newSelect.AddRedundantSelect(new TableAlias());
newSelect = newSelect.RemoveColumn(newSelect.Columns.Single(c => c.Name == COLUMN_NAME));
var newAlias = ((SelectExpression)newSelect.From).Alias;
ColumnExpression rnCol = new ColumnExpression(typeof(int), newAlias, COLUMN_NAME, null);
Expression where;
if (select.Take != null)
{
where = new BetweenExpression(rnCol, Expression.Add(select.Skip, Expression.Constant(1)), Expression.Add(select.Skip, select.Take));
}
else
{
where = rnCol.GreaterThan(select.Skip);
}
if (newSelect.Where != null)
{
where = newSelect.Where.And(where);
}
newSelect = newSelect.SetWhere(where);
select = newSelect;
}
return(select);
}
protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
if (select.Skip != null) {
var newSelect = select.SetSkip(null).SetTake(null).AddRedundantSelect(_language, new TableAlias());
_hasRowNumberExpression = true;
var colType = _language.TypeSystem.GetColumnType(typeof(int));
newSelect = newSelect.AddColumn(new ColumnDeclaration("rownum", new RowNumberExpression(select.OrderBy), colType));
// add layer for WHERE clause that references new rownum column
newSelect = newSelect.AddRedundantSelect(_language, new TableAlias());
newSelect = newSelect.RemoveColumn(newSelect.Columns.Single(c => c.Name == "rownum"));
var newAlias = ((SelectExpression)newSelect.From).Alias;
var rowNumberColumn = new ColumnExpression(typeof(int), colType, newAlias, "rownum");
Expression where;
if (select.Take != null) {
where = new BetweenExpression(rowNumberColumn, Expression.Add(select.Skip, Expression.Constant(1)), Expression.Add(select.Skip, select.Take));
}
else {
where = rowNumberColumn.GreaterThan(select.Skip);
}
if (newSelect.Where != null) {
where = newSelect.Where.And(where);
}
newSelect = newSelect.SetWhere(where);
select = newSelect;
}
return select;
}
private Expression BindAnyAll(Expression source, MethodInfo method, LambdaExpression predicate, bool isRoot)
{
bool isAll = method.Name == "All";
ConstantExpression constSource = source as ConstantExpression;
if (constSource != null && !IsQuery(constSource))
{
System.Diagnostics.Debug.Assert(!isRoot);
Expression where = null;
foreach (object value in (IEnumerable)constSource.Value)
{
Expression expr = Expression.Invoke(predicate, Expression.Constant(value, predicate.Parameters[0].Type));
if (where == null)
{
where = expr;
}
else if (isAll)
{
where = where.And(expr);
}
else
{
where = where.Or(expr);
}
}
return this.Visit(where);
}
else
{
if (isAll)
{
predicate = Expression.Lambda(Expression.Not(predicate.Body), predicate.Parameters.ToArray());
}
if (predicate != null)
{
source = Expression.Call(typeof(Enumerable), "Where", method.GetGenericArguments(), source, predicate);
}
ProjectionExpression projection = this.VisitSequence(source);
Expression result = new ExistsExpression(projection.Select);
if (isAll)
{
result = Expression.Not(result);
}
if (isRoot)
{
if (this.language.AllowSubqueryInSelectWithoutFrom)
{
return GetSingletonSequence(result, "SingleOrDefault");
}
else
{
// use count aggregate instead of exists
var colType = this.language.TypeSystem.GetColumnType(typeof(int));
var newSelect = projection.Select.SetColumns(
new[] { new ColumnDeclaration("value", new AggregateExpression(typeof(int), "Count", null, false), colType) }
);
var colx = new ColumnExpression(typeof(int), colType, newSelect.Alias, "value");
var exp = isAll
? colx.Equal(Expression.Constant(0))
: colx.GreaterThan(Expression.Constant(0));
return new ProjectionExpression(
newSelect, exp, Aggregator.GetAggregator(typeof(bool), typeof(IEnumerable<bool>))
);
}
}
return result;
}
}
private Expression BindAnyAll(Expression source, MethodInfo method, LambdaExpression predicate, bool isRoot)
{
bool isAll = method.Name.Equals("All", StringComparison.InvariantCultureIgnoreCase);
ConstantExpression constSource = source as ConstantExpression;
if (constSource != null && !IsQuery(constSource))
{
System.Diagnostics.Debug.Assert(!isRoot);
Expression where = null;
foreach (object value in (IEnumerable)constSource.Value)
{
Expression expr = Expression.Invoke(predicate, Expression.Constant(value, predicate.Parameters[0].Type));
if (where == null)
{
where = expr;
}
else if (isAll)
{
where = where.And(expr);
}
else
{
where = where.Or(expr);
}
}
return(this.Visit(where));
}
else
{
if (isAll)
{
predicate = Expression.Lambda(Expression.Not(predicate.Body), predicate.Parameters.ToArray());
}
if (predicate != null)
{
source = Expression.Call(typeof(Enumerable), "Where", method.GetGenericArguments(), source, predicate);
}
ProjectionExpression projection = this.VisitSequence(source);
Expression result = new ExistsExpression(projection.Select);
if (isAll)
{
result = Expression.Not(result);
}
if (isRoot)
{
if (this.language.AllowSubqueryInSelectWithoutFrom)
{
return(GetSingletonSequence(result, "SingleOrDefault"));
}
else
{
// use count aggregate instead of exists
//var colType = this.language.TypeSystem.GetColumnType(typeof(int));
var newSelect = projection.Select.SetColumns(new[] { new ColumnDeclaration("value", new AggregateExpression(typeof(int), "Count", null, false)) });
var colx = new ColumnExpression(typeof(int), newSelect.Alias, "value");
var exp = isAll ? colx.Equal(Expression.Constant(0)) : colx.GreaterThan(Expression.Constant(0)); return(new ProjectionExpression(newSelect, exp, Aggregator.GetAggregator(typeof(bool), typeof(IEnumerable <bool>))));
}
}
return(result);
}
}