关于表的联合查询SQL

public static string GetGridViewByTerm3(string perID, string departname, int nameid)
{
return "SELECT Plan_1.Plan_ID,Plan_Time,Plan_PersonID,Plan_Content,Plan_Title,Plan_Kind,Plan_New,Plan_C,Plan_L,Plan_Sta,Plan_Time1,Plan_Depart,Users_RealName FROM (Plan_1 Inner join Plan_To_P on Plan_1.Plan_ID = Plan_To_P.Plan_ID) Inner join Users on Plan_To_P.Plan_P_ID = Users.Users_ID where Plan_PersonID= '" + perID + "' AND Plan_Depart = '" + departname + "' AND Users.Users_ID = " + nameid + " ORDER BY Plan_1.Plan_ID DESC";
}