substr用法,substr

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substr用法,substr

sqlplus conn user/user --串連資料庫

show user --顯示目前使用者

select upper(substr('liufeng',0,3) ) as firstname,lower(substr('liuyuehui',4)) as secondname from dual;--顯示名字

substr('字串',‘開始位置’,'長度');

如果開始位置為負數,代表從字串右側開始找到相應的位置。

如:

select substr('liuyuehui',-3,3)  --輸出結果為hui。

substr從右側向左位移3個字元,然後截取3個字元。輸出為hui。

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