--聚合函数 use pubs go select avg(distinct price) --算平均数 from titles where type='business' go use pubs go select max(ytd_sales) --最大数 from titles go use pubs go select min(ytd_sales) --最小数 from titles go use pubs go select type,sum(price),sum(advance) --求和 from titles group by type order by type go use pubs go select count(distinct city) --求个数 from authors go use pubs go select stdev(royalty) --返回给定表达式中所有值的统计标准偏差 from titles go use pubs go select stdevp(royalty) --返回表达式中所有制的填充统计标准偏差 from titles go use pubs go select var(royalty) --返回所有值的统计方差 from titles go use pubs go select varp(royalty) --返回所有值的填充的统计方差 from titles go (责任编辑:admin) |