/// <summary>
/// N-M行 针对可分页进行调整
/// 方案：
/// 1，根据条件和排序 检索出全部前M行数据(在GetSQLSelectTopClip已经完成了这一步)
/// 2，对这M行数据反转(排序反转)
/// 3，对反转完的数据，取前 M-N+1 行
/// 4，取完数据以后，再次反转
/// 如：select * from (select top [M-N+1] * from (select top [M] * from 表 [order by id desc]) [order by id asc]) [order by id desc]
/// 有一个条件：必须存在排序，如果不存在创建一个
/// </summary>
/// <param name="translater"></param>
/// <returns></returns>
protected virtual void AdjustPagable(ExpressionTranslater translater)
{
var oldSQL = translater.CommandText;
var exp = translater.Expression;
var sql = SQL_PAGING.ToString();
IList <OrderByExpression> orderby = exp.IsOrderBy ? exp.OrderByList : new List <OrderByExpression>()
{
new OrderByExpression(exp.From.GetIdentityField(), OrderByDirection.Asc)
};
sql = sql.Replace("{M_N_1}", (exp.EndIndex.Value - exp.StartIndex.Value + 1).ToString());
sql = sql.Replace("{OLDORDER}", exp.IsOrderBy ? "" : translater.TranslateOrderyByList(orderby, false));
sql = sql.Replace("{REVORDER}", translater.TranslateOrderyByList(orderby, true));
sql = sql.Replace("{ORDER}", translater.TranslateOrderyByList(orderby, false));
sql = sql.Replace("{OLDSQL}", oldSQL);
translater.SetCommandText(sql);
}
