DbQueryRowNumberBuilder IDbSelectQuery.BuildRowNumber(DataSource ds, long top, bool join, string order, bool reverse)
{
DbQueryRowNumberBuilder builder = new DbQueryRowNumberBuilder("WITH CTE AS(SELECT TOP ");
builder.Append(top).Append(" ROW_NUMBER() OVER(").Append(order).Append(")AS _RowNumber,");
if (_select == null || _select.Length == 0)
{
if (join)
{
builder.Append((new DbSelect <T>()).Build(ds));
}
else
{
builder.Append((new DbSelect()).Build(ds));
}
}
else
{
for (int i = 0; i < _select.Length; ++i)
{
if (i > 0)
{
builder.Append(',');
}
builder.Append(_select[i].Build(ds));
}
}
builder.Append(" FROM ").Append(ds.Provider.EscapeName(DbTable.GetTableName <T>()));
return(builder);
}
private IList <dynamic> ExecuteImpl(int size, long page, out long count)
{
bool group = false;
DbQueryBuilder qb = _query.BuildCount(_query.Query.DataSource, 0, false, ref group);
if (group)
{
qb.Append(") AS T").Append(_query.Query.DataSource.PsCount);
}
count = Convert.ToInt64(_query.Query.DataSource.ExecuteScalar(qb.Sql, qb.Parameters));
if (_query.Query.Provider.SupperRowNumber)
{
long half = count / 2;
long lower = (page - 1) * size;
long upper = page * size;
bool reverse = lower > half;
DbQueryRowNumberBuilder builder = _query.BuildRowNumber(_query.Query.DataSource, reverse ? (count - lower) : upper, false, null, reverse);
builder.Append(")SELECT * FROM CTE WHERE _RowNumber>");
if (reverse)
{
builder.Append(count - upper);
}
else
{
builder.Append(lower);
}
if (builder.OrderBy != null)
{
builder.Append(' ').Append(builder.OrderBy);
}
builder.Append(';');
return(_query.Query.DataSource.ExecuteReader(builder.Sql, builder.Parameters));
}
if (_query.Query.Provider.SupperLimit)
{
DbQueryBuilder builder = _query.Build(_query.Query.DataSource, 0, false);
builder.Append(" LIMIT ").Append(size).Append(" OFFSET ").Append((page - 1) * size);
builder.Append(';');
return(_query.Query.DataSource.ExecuteReader(builder.Sql, builder.Parameters));
}
if (_query.Query.Provider.SupperTop)
{
DbQueryBuilder builder = _query.Build(_query.Query.DataSource, page * size, false);
builder.Append(';');
IList <dynamic> list = _query.Query.DataSource.ExecuteReader(builder.Sql, builder.Parameters);
List <dynamic> array = new List <dynamic>(size);
for (long i = ((page - 1) * size); i < list.Count; ++i)
{
array.Add(list[(int)i]);
}
return(array);
}
throw new NotSupportedException();
}
DbQueryRowNumberBuilder IDbSelectQuery.BuildRowNumber(DataSource ds, long top, bool join, string order, bool reverse)
{
StringBuilder osb = new StringBuilder(" ORDER BY ");
for (int i = 0; i < _order.Length; ++i)
{
if (i > 0)
{
osb.Append(',');
}
osb.Append(_order[i].BuildBase(ds));
}
StringBuilder tsb = new StringBuilder(osb.Length);
tsb.Append("ORDER BY ");
if (reverse)
{
for (int i = 0; i < _order.Length; ++i)
{
if (i > 0)
{
tsb.Append(',');
}
tsb.Append(_order[i].BuildReverse(ds));
}
}
else
{
for (int i = 0; i < _order.Length; ++i)
{
if (i > 0)
{
tsb.Append(',');
}
tsb.Append(_order[i].Build(ds));
}
}
string torder = tsb.ToString();
DbQueryRowNumberBuilder builder = _query.BuildRowNumber(ds, top, join, torder, reverse);
builder.OrderBy = osb.ToString();
builder.Append(' ').Append(torder);
return(builder);
}
