在 Oracle 中拆分列

如果没有正则表达式，您需要为您需要的每个子字符串回复相同的逻辑，每个 timi 都根据该子字符串的“终止符”的位置选择初始位置和长度。

/* input data */
    with yourTable(column1) as (
        select '/opt/log/data/abcd.efghi.jklmn.aaa.txt' from dual union all
        select '/opt/log/data/abbbcd.efccghi.jkdsdflmn.abab.txt' from dual union all
        select '/opt/log/data/nmvcnmcd.efjhjghi.jkvslmn.abcbc.txt' from dual union all
        select '/opt/log/data/hjsdhj.hjfdhdf.hdfhjd.aghag.txt' from dual union all
        select '/opt/log/data/dfhjfdhj.yureyer.qwtyq.hjahjh.txt' from dual
    )
/* query */
    select substr(column1, instr(column1, '/', -1) +1, instr(column1, '.') - instr(column1, '/', -1)-1) firstDot,
           substr(column1, instr(column1, '.') +1, instr(column1, '.', 1, 2) - instr(column1, '.') -1) secondDot,
           substr(column1, instr(column1, '.', 1, 2) +1, instr(column1, '.', 1, 4) - instr(column1, '.', 1, 2) -1) thirdAndFourthDot
    from yourTable 

给出：

FIRSTDOT        SECONDDOT       THIRDANDFOURTHD
--------------- --------------- ---------------
abcd            efghi           jklmn.aaa
abbbcd          efccghi         jkdsdflmn.abab
nmvcnmcd        efjhjghi        jkvslmn.abcbc
hjsdhj          hjfdhdf         hdfhjd.aghag
dfhjfdhj        yureyer         qwtyq.hjahjh

以更易读的方式：

select substr(column1, lastSlashPos +1, firstDotPos - lastSlashPos -1) as firstDot,
       substr(column1, firstDotPos +1, secondDotPos - firstDotPos -1) as secondDot,
       substr(column1, secondDotPos +1, fourthDotPos - secondDotPos -1) as thirdAndFourthDot
from (
        select instr(column1, '/', -1) as lastSlashPos,
               instr(column1, '.') as firstDotPos,
               instr(column1, '.', 1, 2) as secondDotPos,
               instr(column1, '.', 1, 3) as thirdDotPos,
               instr(column1, '.', 1, 4) as fourthDotPos,
               column1
        from yourTable
     )