導(dǎo)讀:1建站知識(shí)1.大小寫轉(zhuǎn)換 initcap(char) 把每個(gè)字符串的首字符換成大寫 lower(char) 整個(gè)字符串轉(zhuǎn)換成小寫 upper(char) 整個(gè)字符串轉(zhuǎn)換成網(wǎng)站seo優(yōu)化軟件網(wǎng)站seo優(yōu)化診斷工具。

1.大小寫轉(zhuǎn)換

initcap(char) 把每個(gè)字符串的首字符換成大寫

upper(char) 整個(gè)字符串轉(zhuǎn)換成大寫

BYS@bys1>Select lower(ename),upper(ename),initcap(ename) from emp where rownum<3; LOWER(ENAM UPPER(ENAM INITCAP(EN ---------- ---------- ---------- smith      SMITH      Smith allen      ALLEN      Allen

2.字符連接CONCAT和||

CONCAT (char1, char2)    連接char1和char2，注意：CONCAT只能連接兩個(gè)字符串，連接三個(gè)將報(bào)錯(cuò)。

BYS@bys1>select ename,job,ename,concat(ename,job) from emp where rownum<3; ENAME      JOB       ENAME      CONCAT(ENAME,JOB) ---------- --------- ---------- ------------------- SMITH      CLERK     SMITH      SMITHCLERK ALLEN      SALESMAN  ALLEN      ALLENSALESMAN BYS@bys1>select ename,job,ename,concat(ename,job,ename) from emp where rownum<3; select ename,job,ename,concat(ename,job,ename) from emp where rownum<3         seo網(wǎng)站優(yōu)化               * ERROR at line 1: ORA-00909: invalid number of arguments

||連接符，一大優(yōu)勢(shì)是可以在連續(xù)符中間添加指定的字符

BYS@bys1>select ename,job,ename,ename||ename||job from emp where rownum<3; ENAME      JOB       ENAME      ENAME||ENAME||JOB ---------- --------- ---------- ----------------------------- SMITH      CLERK     SMITH      SMITHSMITHCLERK ALLEN      SALESMAN  ALLEN      ALLENALLENSALESMAN

BYS@bys1>select ename,job,ename,'mingzi '||ename||ename||'  gongzuo  '||job from emp where rownum<3; ENAME      JOB       ENAME      'MINGZI'||ENAME||ENAME||'GONGZUO'||JOB ---------- --------- ---------- ----------------------------------------------- SMITH      CLERK     SMITH      mingzi SMITHSMITH  gongzuo CLERK ALLEN      SALESMAN  ALLEN      mingzi ALLENALLEN  gongzuo  SALESMAN

關(guān)鍵詞標(biāo)簽: 函數(shù) 之二