1.decode 函数（小版本的case when）
select decode(pd.discount_id,null,'','购买'||pd.product_count||'个，'||pd.product_discount_rate||'折优惠') as discount
from b2b_product d right join b2b_product_hot ph on d.product_id = ph.product_id left join b2b_dictionary a
on d.RRO_MARQUE = a.CODE left join b2b_dictionaryindex b on d.RRO_BRAND = b.INDEXCODE
left join b2b_company c on d.COMPANY_ID = c.COMPANY_ID
left join b2b_product_discount pd on pd.product_id = d.product_id
order by ph.sort, ph.pro_type;
2.varchar排序
select p.code,
case
when p.state = '0' then
decode(b.state, '1', '1', '0' )
when p.state = '1' then
decode(b.state, '0', '0', '1' )
end as
from b2b_paytype_dic p, b2b_buyer_paytype b
where p.code = b.paytype_code(+)
and (b.buyer_id = ' ' or b.id is null)
order by to_number(p.code)
3.case then 语句
select case when order_state= 2 then '已兑换' when order_state= 3 then '交易成功' end ORDER_STATE , sum(order_count) as cnt from t_report_order t where 1=1
4.手机号的显示sql 例如 （158****2640）
select substr(r.mobile,1,3)||'****'||substr(r.mobile,8) as mobile from t_prize_record r;
5.给某个表备份
select * into xyq_college_20120301（表的别名） from xyq_college(表名)6.convert 截取时间
select * from vas_mt_viewmt where phone ='15966605352' and convert(nvarchar (10),createtime,121)='2011-09-14'7.--将 字符串时间列，统一转化为时间，并减一
update wfjs_useStats_woman
set createdate=convert(varchar(10),cast(createdate as datetime)-1,120)
8.只复制表结构的sql
create table b as select * from a where 1<>1
9.即复制表结构又复制表中数据的sql
create table b as select * from a
10、将多个表数据插入一个表中
insert into 目标表test(字段1。。。字段n) (select 字段1.。。。。字段n) from 表 union all select 字段1.....字段n from 表
