/// <summary>作为子查询</summary>
/// <param name="alias">别名，某些数据库可能需要使用as</param>
/// <returns></returns>
public SelectBuilder AsChild(String alias = null)
{
SelectBuilder t = this;
// 如果包含排序，则必须有Top，否则去掉
Boolean hasOrderWithoutTop = !String.IsNullOrEmpty(t.OrderBy) && !ColumnOrDefault.StartsWith("top ", StringComparison.OrdinalIgnoreCase);
if (hasOrderWithoutTop)
{
t = this.Clone();
t.OrderBy = null;
}
SelectBuilder builder = new SelectBuilder();
if (String.IsNullOrEmpty(alias))
{
builder.Table = String.Format("({0})", t.ToString());
}
else
{
builder.Table = String.Format("({0}) {1}", t.ToString(), alias);
}
// 把排序加载外层
if (hasOrderWithoutTop)
{
builder.OrderBy = this.OrderBy;
}
return(builder);
}
/// <summary>作为子查询</summary>
/// <param name="alias">别名，某些数据库可能需要使用as</param>
/// <param name="trimOrder">SqlServer需要转移OrderBy到外层，Oracle则不能</param>
/// <returns></returns>
public SelectBuilder AsChild(String alias, Boolean trimOrder)
{
var t = this;
// 如果包含排序，则必须有Top，否则去掉
var hasOrderWithoutTop = false;
if (trimOrder)
{
hasOrderWithoutTop = !String.IsNullOrEmpty(t.OrderBy) && !ColumnOrDefault.StartsWithIgnoreCase("top ");
}
if (hasOrderWithoutTop)
{
t = Clone();
t.OrderBy = null;
}
var builder = new SelectBuilder();
if (String.IsNullOrEmpty(alias))
{
builder.Table = String.Format("({0})", t.ToString());
}
else
{
builder.Table = String.Format("({0}) {1}", t.ToString(), alias);
}
// 把排序加载外层
if (hasOrderWithoutTop)
{
builder.OrderBy = OrderBy;
}
builder.Parameters.AddRange(Parameters);
return(builder);
}
