1、查詢當前月和前一個月的資料

新增一個擴充套件方法AddMonth

public static ISugarQueryable<T> AddMonth<T>(this ISugarQueryable<T> queryable, int month = -1,
            DateTime? date = null) where T : class, new()
        {
            if (date == null)
            {
                date = DateTime.Today;
            }
            DateTime newDate 
 
= (DateTime)date;
            List<string> sqlList = new List<string>();
            for (int i = month; i <= 0; i++)
            {
                var datestr = newDate.AddMonths(i).ToString("yyMM");
                var newq = queryable.Clone().AS($"{queryable.SqlBuilder.GetNoTranslationColumnName(queryable.QueryBuilder.EntityName)}{datestr}
 
");
                var sql = newq.ToSqlString();
                sqlList.Add(sql);
            }
            var sqlstr = string.Join("\r\nUnion All\r\n", sqlList);
            var queryabler = queryable.Context.SqlQueryable<T>(sqlstr);
            return queryabler;
        }

2、查詢一段時間跨度的資料

新增一個擴充套件方法Between

public static ISugarQueryable<T> Between<T>(this ISugarQueryable<T> queryable, int start, int end,
            DateTime? date = null) where T : class, new()
        {
            if (date == null)
            {
                date = DateTime.Today;
            }
            DateTime newDate = (DateTime)date;
            List<string> sqlList = new List<string>();
            for (int i = start; i <= end; i++)
            {
                var datestr = newDate.AddMonths(i).ToString("yyMM");
                var newq = queryable.Clone().AS($"{queryable.SqlBuilder.GetNoTranslationColumnName(queryable.QueryBuilder.EntityName)}{datestr}");
                var sql = newq.ToSqlString();
                sqlList.Add(sql);
            }
            var sqlstr = string.Join("\r\nUnion All\r\n", sqlList);
            var queryabler = queryable.Context.SqlQueryable<T>(sqlstr);
            return queryabler;
        }

3、測試方法

var ssc = SqlFuncEx.GetDB("server=127.0.0.1;database=SQLSUGAR4XTEST;uid=sa;pwd=123456");
            var sql = ssc.Queryable<Student>().AddMonth().ToSqlString();
            var sql2 = ssc.Queryable<Student, School>((st, sc) => st.SchoolId == sc.Id).AddMonth().ToSqlString();
            var sql3 = ssc.Queryable<Student, School>((st, sc) => st.SchoolId == sc.Id)
                .Select((st, sc) =>new Student
                {
                    Id = st.Id,
                    Name = st.Name
                })
                .AddMonth().ToSqlString();

Demo地址：https://gitee.com/xuanyun2018/sqlsugardemo.git