Linq to Entities 比较子查询中的日期时间

Question

我正在尝试执行此子查询：

var query = 
    from cjto in oContext.t_table_1
    join cav in oContext.t_table_2 on cjto.cd_code equals cav.cd_code
    where cav.dt_time >= 
        (from tu in oContext.t_table3
        where tu.vl_code == "ABCD"
        select tu.dt_check_time)
    select cav;

但是，我收到错误：

Operator '>=' cannot be applied to operands of type 'System.DateTime' and 'System.Linq.IQueryable<System.DateTime?>'

如何实现此类查询？
塔克斯

Answer 1

好的，我明白了...我需要添加 FirstOrDefault() 以便获取第一个元素

var query = 
    from cjto in oContext.t_table_1
    join cav in oContext.t_table_2 on cjto.cd_code equals cav.cd_code
    where cav.dt_time >= 
        (from tu in oContext.t_table3
        where tu.vl_code == "ABCD"
        select tu.dt_check_time).FirstOrDefault()
    select cav;

Tks