1 计算记录的总数
SELECT COUNT(ID) FROM TABLE (WHERE...) where条件视情况加
2计算某列的和
SELECT SUM(数字字段) AS SUMCOUNT FROM TABLENAME;
3查询字段的最大最小
SELECT MAX(字段) FROM TABLENAME
SELECT MIN(字段) FROM TABLENAME
4排序
SELECT 字段1,字段2,字段3 ... FROM TABLENAME ORDER BY 字段