The demand of a recent customer is really abnormal .

A system number string is required , String by 3 Part composition , The first two are Pinyin abbreviations of Chinese characters , It's not difficult .

The last part is one 4 Pure number of digits from 0001~9999,

Every time you insert a piece of data, you have to judge whether 0001 Start to 9999 between , The first number that doesn't exist , If the number has been reached, it will not be repeated , Possible continuity ,( If it is not deleted, you only need to retrieve it every time max+1 that will do , However, it may be deleted in the middle , There is a disconnection , Then the newly inserted data must be filled in ).

Now the idea is to take a list , Sort by number , And then rownu Go and compare , And then rownum Compare it with his number number

rownum      ||    systemno

1             1

2             2

3             3

4             4

5             5

6             7

So find the first one rownum Unequal numbers are not impossible

select min(rn) from (
select rownum rn,bts_system_no from (select bts_system_no from bo_bts where
bts_system_no is not null
 order by to_number(bts_system_no))) where  rn < to_number(bts_system_no)

Basically, we can get the first number 6

Technology
©2019-2020 Toolsou All rights reserved,
Python Garbage collection and memory leak hive Summary of processing methods for a large number of small files The difference between memory overflow and memory leak , Causes and Solutions Create data mysql Library process You don't know ——HarmonyOS stay Vue Use in Web WorkerSparkSQL Achieve partition overlay write msf Generate Trojan horse attack android mobile phone Linux Page replacement algorithm C Language implementation Django Personal blog building tutorial --- Time classified archiving