1、如下图，c.industryId作为string类型当作参数传递，解析时会加单引号，即：”c.industryId“，

生成的查询语句就会变成

-- 这里把'c.IndustryGroup' 当成实际的值所以会查询不出数据

select b.`Name`,COUNT(c.Id) Num
                           from base_industry_dist b
                           LEFT JOIN base_companyinfo c on b.Id='c.IndustryGroup'
                           Where b.Deep=0 GROUP BY b.Id ORDER BY num

可修改成如下：

--使用$语法糖的写法可读性高，代码简洁

        /// <summary>
        /// 获取产业所属企业数量统计
        /// </summary>
        /// <param name="id"></param>
        /// <param name="deep"></param>
        /// <returns></returns>
        public async Task<List<IndustryCompanyStatistictQto>> GetIndustryCompanyStatistictsAsync(Guid? id, int deep)
        {
            var sqlStr = @$"select b.`Name`,COUNT(c.Id) Num 
                           from base_industry_dist b ";
            var whereStr = @" Where b.Deep=@deep";

            var groupByStr = @" GROUP BY b.Id ORDER BY Num desc";

            var industryId = "c.IndustryGroup";
            var sqlPredicates = new List<string>();
            var queryParam = new DynamicParameters();
            queryParam.Add(nameof(deep), deep);
            if (deep == 1)
            {
                industryId = "c.IndustrySubGroup";
                sqlPredicates.Add(" b.ParentId=@parentId");
                queryParam.Add("parentId", id.Value);
            }
            else if (deep == 2)
            {
                industryId = "c.IndustrySpecific";
                sqlPredicates.Add(" b.ParentId=@parentId");
                queryParam.Add("parentId", id.Value);
            }
            else
            {
                queryParam.Add(nameof(industryId), industryId);
            }

            var leftJoinStr = @$" LEFT JOIN base_companyinfo c on b.Id={industryId}";
            sqlStr += leftJoinStr;
            sqlStr += whereStr;
            if (sqlPredicates.Any())
            {
                var sqlPredicatesStr = sqlPredicates.Aggregate((p, n) => $"{p} and {n}");
                sqlStr = @$"{sqlStr} 
                              and {sqlPredicatesStr}";
            }

            sqlStr += groupByStr;

            var connect = await GetDbConnectionAsync();
            var dbTransaction = await GetDbTransactionAsync();

            //var tt = (await connect.QueryAsync(sqlStr, queryParam, dbTransaction)).ToList();

            return (await connect.QueryAsync<IndustryCompanyStatistictQto>(sqlStr, queryParam, dbTransaction)).ToList();
        }