sqlite的拼接字段的方法（sqlite没有convert函数）

我在sqlserver 操作方式：

   /// <summary>
    ///获取当前门店工资列表
    /// </summary>
    /// <param name="wheres">其他条件</param>
    /// <param name="ThisMendian">当前门店</param>
    /// <param name="IsNotUseYearMonth">是否需要单一的年月来获取工资</param>
    /// <returns></returns>
    public IEnumerable<GongziInfos> QueryListByMendianInWhere(string wheres ,bool IsNotUseYearMonth)
    {
        string Top = string.IsNullOrWhiteSpace(wheres) ? "Top 1000" : string.Empty; 
        string sql = $@"SELECT  {Top} * from ( 
                       select  *, cast(CONVERT( varchar,Year)+ '-'+CONVERT(varchar,Month)+'-15' as Date) as SetGongziDate FROM [GongziInfos]) a
                       Where 1 = 1 {wheres} ";
        return DapperDbHelper.Query<GongziInfos>(sql);
    }

替换为sqlite的操作：

        /// <summary>
        ///获取当前门店工资列表
        /// </summary>
        /// <param name="wheres">其他条件</param>
        /// <param name="ThisMendian">当前门店</param>
        /// <param name="IsNotUseYearMonth">是否需要单一的年月来获取工资</param>
        /// <returns></returns>
        public IEnumerable<GongziInfos> QueryListByMendianInWhere(string wheres, bool IsNotUseYearMonth)
        {
            string Top = string.IsNullOrWhiteSpace(wheres) ? "limit 100" : string.Empty;
            string sql = $@"SELECT  * from ( 
                           select  *, cast(Year+'-'+Month+'-15' as Date) as SetGongziDate FROM [GongziInfos]) a
                           Where 1 = 1 {wheres} {Top} ";
            //return DapperDbHelper.Query<GongziInfos>(sql);
            using (IDbConnection Conn = new DALDBBase().GetOpenConn())
            {
                return Conn.Query<GongziInfos>(sql);
            }
        }