/// <summary>
/// 转换 DATEDIFF 表达式
/// </summary>
/// <param name="expression">表达式</param>
private void convertDateDiff(MethodCallExpression expression)
{
System.Collections.ObjectModel.ReadOnlyCollection <System.Linq.Expressions.Expression> arguments = expression.Arguments;
SqlStream.SimpleWrite("datediff(");
whereExpression.Convert(arguments[0]);
if (whereExpression.Type == WhereExpression.ConvertType.ConvertExpression)
{
ExpressionCallDateDiffType type = (ExpressionCallDateDiffType)whereExpression.Expression.GetConstantValue();
if (type != ExpressionCallDateDiffType.NONE)
{
SqlStream.Write(type.ToString());
SqlStream.Write(',');
}
}
else
{
throw new InvalidCastException("未知函数表达式参数值类型 " + expression.Method.Name + " " + whereExpression.Expression.NodeType.ToString());
}
convert(arguments[1]);
SqlStream.Write(',');
convert(arguments[2]);
SqlStream.Write(')');
}
/// <summary>
/// 计算时间差
/// </summary>
/// <param name="DateDiffType"></param>
/// <param name="StartTime"></param>
/// <param name="EndTime"></param>
/// <returns></returns>
public static int DateDiff(ExpressionCallDateDiffType DateDiffType, DateTime StartTime, DateTime EndTime)
{
return(0);
}