protected override Expression VisitOver(SqlOverExpression expression)
{
SqlOverExpression current;
if (!this.TryGetCurrent(expression, out current))
{
return(expression);
}
foreach (var value in expression.OrderBy)
{
this.Visit(value);
if (!result)
{
return(expression);
}
}
if (!result)
{
return(expression);
}
this.Visit(expression.Source);
if (!result)
{
return(expression);
}
return(expression);
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
if (selectExpression.Skip != null)
{
var rowNumber = new SqlFunctionCallExpression(typeof(int), "ROW_NUMBER");
var over = new SqlOverExpression(rowNumber, selectExpression.OrderBy ?? new ReadOnlyList<Expression>(new [] { new SqlOrderByExpression(OrderType.Ascending, selectExpression.Columns[0].Expression) }));
var additionalColumn = new SqlColumnDeclaration(RowColumnName, over);
var newAlias = selectExpression.Alias + "INNER";
var innerColumns = new ReadOnlyList<SqlColumnDeclaration>(selectExpression.Columns.Select(c => c).Concat(new[] { additionalColumn }));
var innerSelect = new SqlSelectExpression(selectExpression.Type, newAlias, innerColumns, selectExpression.From, selectExpression.Where, null, selectExpression.GroupBy, selectExpression.Distinct, null, null, selectExpression.ForUpdate);
var outerColumns = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, newAlias, c.Name)));
Expression rowPredicate = Expression.GreaterThan(new SqlColumnExpression(typeof(int), newAlias, additionalColumn.Name), selectExpression.Skip);
if (selectExpression.Take != null && !(selectExpression.Take is SqlTakeAllValueExpression))
{
rowPredicate = Expression.And
(
rowPredicate,
Expression.LessThanOrEqual(new SqlColumnExpression(typeof(int), newAlias, additionalColumn.Name), Expression.Add(selectExpression.Skip, selectExpression.Take))
);
}
return new SqlSelectExpression(selectExpression.Type, selectExpression.Alias, outerColumns, innerSelect, rowPredicate, null, selectExpression.ForUpdate);
}
return base.VisitSelect(selectExpression);
}
protected override Expression VisitOver(SqlOverExpression expression)
{
SqlOverExpression current;
if (!TryGetCurrent(expression, out current))
{
return expression;
}
if (!(this.result &= current.NodeType == expression.NodeType))
{
return expression;
}
if (!(this.result &= current.Type == expression.Type))
{
return expression;
}
this.currentObject = current.Source;
this.Visit(expression.Source);
if (!this.result)
{
return expression;
}
this.currentObject = current.OrderBy;
this.VisitExpressionList(expression.OrderBy);
if (!this.result)
{
return expression;
}
this.currentObject = current;
return expression;
}
protected virtual Expression VisitOver(SqlOverExpression expression)
{
var source = this.Visit(expression.Source);
var orderBy = this.VisitExpressionList(expression.OrderBy);
if (source != expression.Source || orderBy != expression.OrderBy)
{
return(new SqlOverExpression(source, orderBy));
}
return(expression);
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
if (selectExpression.Skip != null)
{
var rowNumber = new SqlFunctionCallExpression(typeof(int), "ROW_NUMBER");
var oldAliases = (selectExpression.From as ISqlExposesAliases)?.Aliases;
var innerSelectWithRowAlias = selectExpression.Alias + "_ROW";
var cols = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, selectExpression.Alias, c.Name))).ToList();
var over = new SqlOverExpression(rowNumber, selectExpression.OrderBy?.ToReadOnlyCollection() ?? cols.Select(c => new SqlOrderByExpression(OrderType.Ascending, c.Expression)).ToReadOnlyCollection());
if (oldAliases != null)
{
over = (SqlOverExpression)AliasReferenceReplacer.Replace(over, oldAliases.Contains, selectExpression.Alias);
}
var rowColumn = new SqlColumnDeclaration(RowColumnName, over);
cols.Add(rowColumn);
var innerSelectWithRowColumns = cols.ToReadOnlyCollection();
var innerSelectWithRow = new SqlSelectExpression(selectExpression.Type, innerSelectWithRowAlias, innerSelectWithRowColumns, this.Visit(selectExpression.ChangeOrderBy(null).ChangeSkipTake(null, null)), null, null, null, false, null, null, false);
var outerColumns = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, innerSelectWithRowAlias, c.Name)));
Expression rowPredicate = Expression.GreaterThan(new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name), selectExpression.Skip);
if (selectExpression.Take != null && !(selectExpression.Take is SqlTakeAllValueExpression))
{
rowPredicate = Expression.And
(
rowPredicate,
Expression.LessThanOrEqual(new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name), Expression.Add(selectExpression.Skip, selectExpression.Take))
);
}
var retval = new SqlSelectExpression(selectExpression.Type, selectExpression.Alias, outerColumns.ToReadOnlyCollection(), innerSelectWithRow, rowPredicate, null, null, selectExpression.Distinct, null, null, selectExpression.ForUpdate, selectExpression.Reverse, selectExpression.Into);
return retval;
}
return base.VisitSelect(selectExpression);
}
protected override Expression VisitOver(SqlOverExpression selectExpression)
{
this.Visit(selectExpression.Source);
this.Write(" OVER (ORDER BY ");
this.WriteDeliminatedListOfItems<Expression>(selectExpression.OrderBy, c =>
{
this.Visit(c);
if (((SqlOrderByExpression)c).OrderType == OrderType.Descending)
{
this.Write(" DESC");
}
});
this.Write(")");
return selectExpression;
}
protected override Expression VisitOver(SqlOverExpression expression)
{
// TODO
return(base.VisitOver(expression));
}
protected virtual Expression VisitOver(SqlOverExpression expression)
{
var source = this.Visit(expression.Source);
var orderBy = this.VisitExpressionList(expression.OrderBy);
if (source != expression.Source || orderBy != expression.OrderBy)
{
return new SqlOverExpression(source, orderBy);
}
return expression;
}
protected override Expression VisitOver(SqlOverExpression selectExpression)
{
this.Visit(selectExpression.Source);
this.Write(" OVER (ORDER BY ");
this.WriteDeliminatedListOfItems<Expression>(selectExpression.OrderBy, c =>
{
this.Visit(c);
});
this.Write(")");
return selectExpression;
}