需求:
1、有一张凭证表名为vouch(vouchid,vouchdesc),凭证号vouchid(varchar类型)为主键,vouchdesc为凭证描述;
2、凭证号的格式为字母加数字,字母代表凭证类型,数字代表凭证编号,如“c-100”代表编号为100的存折凭证;
2、现需要批量生成1000条存证凭证,凭证起始号为当前库里的最大凭证号+1,假设当前最大号为“c-100";
方案:
sql片段如下:
select max(replace(vouchid,'C-','')) into lvnMaxVouchid from vouch;
insert into vouch
(vouchid, vouchdesc)
select 'C-' || (lvnMaxVouchid + rownum), '存折-' || (lvnMaxVouchid + rownum)
from dual
connect by level <= 1000
运行:没问题。
再次运行:报错-"违反唯一约束条件"。
调试:发现再次运行时取到的lvnMaxVouchid 变量的值是999,奇怪?应该是1000啊!
找原因:vouchid是varchar类型,不是number类型,max的时候不会按字段代表的[数值大小]进行判断的,需要先to_number操作。
select max(to_number(replace(vouchid,'C-',''))) into lvnMaxVouchid from vouch;