/// <summary>
/// NOT BETWEEN...AND 子句。
/// </summary>
/// <param name="fieldOrexp">字段信息或表达式。</param>
/// <param name="start">开始值。</param>
/// <param name="end">结束值。</param>
/// <returns></returns>
public static FunDescription NotBetweenAnd(object fieldOrexp, object start, object end)
{
FunDescription f = new FunDescription();
f.FunctionName = "NOTBETWEENAND";
f.Parameter = new object[] { fieldOrexp, start, end };
return(f);
}
/// <summary>
/// IS NOT NULL 函数。
/// </summary>
/// <returns></returns>
public FunDescription IsNotNull()
{
FunDescription f = new FunDescription();
f.FunctionName = "ISNOTNULL";
f.Parameter = this;
return(f);
}
/// <summary>
/// 字符串截取函数。
/// </summary>
/// <param name="str">要截取的字符串。</param>
/// <param name="start">开始截取的位置。</param>
/// <param name="length">截取数量。</param>
/// <returns></returns>
public static FunDescription Substring(object expression, int start, int length)
{
FunDescription f = new FunDescription();
f.FunctionName = "SUBSTRING";
f.Parameter = new object[] { expression, start, length };
return(f);
}
/// <summary>
/// IS NOT NULL 函数。
/// </summary>
/// <param name="parameter">参数（一般为字段信息）。</param>
/// <returns></returns>
public static FunDescription IsNotNull(object parameter)
{
FunDescription f = new FunDescription();
f.FunctionName = "ISNOTNULL";
f.Parameter = parameter;
return(f);
}
/// <summary>
/// 获取长度函数。
/// </summary>
/// <param name="parameter">函数参数。</param>
/// <returns></returns>
public static FunDescription Len(object parameter)
{
FunDescription f = new FunDescription();
f.FunctionName = "LEN";
f.Parameter = parameter;
return(f);
}
/// <summary>
/// 返回给定日期整型部份的数据。
/// </summary>
/// <param name="interval">日期时间中对应的部份。
/// <para>SQLite不支持此函数。</para>
/// </param>
/// <param name="thedate">日期时间。</param>
/// <returns></returns>
public static FunDescription DatePart(DateInterval interval, object thedate)
{
FunDescription f = new FunDescription();
f.FunctionName = "DATEPART";
f.Parameter = new object[] { interval, thedate };
return(f);
}
/// <summary>
/// 获取当前日期时间函数。
/// </summary>
/// <param name="parameter">函数参数。</param>
/// <returns></returns>
public static FunDescription Now(object parameter = null)
{
FunDescription f = new FunDescription();
f.FunctionName = "NOW";
f.Parameter = parameter;
return(f);
}
/// <summary>
/// 统计函数。
/// </summary>
/// <param name="parameter">函数参数。</param>
/// <returns></returns>
public static FunDescription Count(object parameter)
{
FunDescription f = new FunDescription();
f.FunctionName = "COUNT";
f.Parameter = parameter;
return(f);
}
/// <summary>
/// 去重复值的字段列表。
/// </summary>
/// <param name="parameter">字段列表（单个或多个字段，注：某些数据库可能不支持多字段去重复值）。</param>
/// <returns></returns>
public static FunDescription Distinct(params FieldDescription[] parameter)
{
FunDescription f = new FunDescription();
f.FunctionName = "DISTINCT";
f.Parameter = parameter;
return(f);
}
/// <summary>
/// 表达式的 NotIn 函数支持.
/// </summary>
/// <param name="values"></param>
/// <returns></returns>
public FunDescription NotIn(object[] values)
{
FunDescription f = new FunDescription();
f.FunctionName = "NOTIN";
List <object> buf = new List <object>();
buf.Add(this);
buf.AddRange(values);
f.Parameter = buf.ToArray();
return(f);
}
/// <summary>
/// 表达式的 NotIn 函数支持.
/// </summary>
/// <param name="select">条件查询.</param>
/// <returns></returns>
public FunDescription NotIn(IDescription select)
{
FunDescription f = new FunDescription();
f.FunctionName = "NOTIN";
List <object> buf = new List <object>();
buf.Add(this);
buf.Add(select);
f.Parameter = buf.ToArray();
return(f);
}
/// <summary>
/// IN 函数。
/// </summary>
/// <param name="field">字段信息。</param>
/// <param name="values">In函数的值。</param>
/// <returns></returns>
public static FunDescription In(FieldDescription field, object[] values)
{
FunDescription f = new FunDescription();
f.FunctionName = "IN";
List <object> buf = new List <object>();
buf.Add(field);
buf.AddRange(values);
f.Parameter = buf.ToArray();
return(f);
}
/// <summary>
/// IN 函数。
/// </summary>
/// <param name="field">字段信息。</param>
/// <param name="select">嵌套子查询。</param>
/// <returns></returns>
public static FunDescription In(FieldDescription field, IDescription select)
{
FunDescription f = new FunDescription();
f.FunctionName = "IN";
List <object> buf = new List <object>();
buf.Add(field);
buf.Add(select);
f.Parameter = buf.ToArray();
return(f);
}
