1>to_char,将日期转换为字符；add_months,在第一个参数的日期上加或者减第二个参数的值；

select dkzh,jkhtbh,yhkrq,dkffrq,shqs,dqyqcs,to_char(add_months(dkffrq,shqs+dqyqcs+1),'yyyymm') from grdk_dk_zz a where a.dkzt in('02','03') and jgbm like '01'||'%' and to_char(a.yhkrq,'yyyymm')<>to_char(add_months(a.dkffrq,a.shqs+a.dqyqcs+1),'yyyymm');

      2>avg，取平均值；round,保留第二个参数的几位小数，四舍五入；

select jkhtbh, round(avg(fse), 2) fse

from (select jkhtbh, hkqs, sum(fse) fse

from grdk_dk_hkmx

where hkqs >=

to_char(add_months(sysdate, -3), 'yyyymm')

and jgbm like  '01%'

and hkzt in ('02', '03', '05')

group by jkhtbh, hkqs)

group by jkhtbh;

   3>lpad函数将左边的字符串填充一些特定的字符其语法格式如下：lpad(string,n,[pad_string])

v_mm:=lpad(to_char(v_yd1),2,'0');

     4>last_day函数返回一个月最后一天

while v_yhkrq<=(case when v_sf01=0 then v_shrq else last_day(v_shrq) end) and v_dkye>0 and v_shqs<v_dkqs

   5>upper( 字符串)，返回字符串的大写

select VIEW_DEFINITION from v$fixed_view_definition where view_name=upper('v$fixed_view_definition');

  6>substr(字符串,数字，数字),截取一段字符串

select kmmc from cw_pz_fl where kmbh like '21905%';

select substr(kmmc,14,12) from cw_pz_fl where kmbh like '21905%';

7>instr(a,b) ,a字符串是否包含b字符串

select f_newid,d.kfsbm,c.jzrq,c.jzrq,a.xmbh,a.jgbm,' ',c.dffse,'期房贷款',0,0,' ',' ',' ',0,' ',0,0,0,' ','01',' ',0,f_hfsc_max_pzbh(a.jgbm,'0302'),' ',0,1,' ',' ',null,0,0,0,0,0,82,3521,'zxb',f_hfsc_max_pzbh(a.jgbm,'0302'),'伍芳',a.jkrxm,a.jkrzjh,a.jkhtbh,' ','伍芳',' '

from grdk_sq_htxx a,

(select *

from cw_pz_fl b

where b.jzrq between date '2018-01-01' and date

'2018-12-31'

and b.kmbh like '21905%'

and b.jffse = 0) c,

grdk_sfdw d

where instr(c.zhaiyao, a.jkrxm) > 0 and a.wtskkhdwmc=d.kfsmc;

8>trunc    去掉时分秒，保留年月日

v_hdrq      date:=trunc(sysdate);

9>nvl(a,0),如果a为空，就取第二个数值零；

select count(*),nvl(sum(gryjce+dwyjce+bcyjce+czybte),0) into v_hjrs2,v_hjje2 from gjzf_gr_zz

where  dwzh=v_dwzh and grzhzt='01' and jzny=v_rq ;