# concat函数

```SQL> select ename,job,concat(ename,job) from emp;
ENAME      JOB       CONCAT(ENAME,JOB)
---------- --------- -------------------
SMITH      CLERK     SMITHCLERK
ALLEN      DBA       ALLENDBA
WARD       DBA       WARDDBA
JONES      MANAGER   JONESMANAGER
MARTIN     DBA       MARTINDBA
BLAKE      DBA       BLAKEDBA
CLARK      MANAGER   CLARKMANAGER
SCOTT      ANALYST   SCOTTANALYST
KING       PRESIDENT KINGPRESIDENT
TURNER     DBA       TURNERDBA
JAMES      DBA       JAMESDBA
FORD       ANALYST   FORDANALYST
MILLER     CLERK     MILLERCLERK
14 rows selected
```
```SQL> select ename,job,concat(ename,'s job is ' || job) from emp;
ENAME      JOB       CONCAT(ENAME,'SJOBIS'||JOB)
---------- --------- ----------------------------
SMITH      CLERK     SMITHs job is CLERK
ALLEN      DBA       ALLENs job is DBA
WARD       DBA       WARDs job is DBA
JONES      MANAGER   JONESs job is MANAGER
MARTIN     DBA       MARTINs job is DBA
BLAKE      DBA       BLAKEs job is DBA
CLARK      MANAGER   CLARKs job is MANAGER
SCOTT      ANALYST   SCOTTs job is ANALYST
KING       PRESIDENT KINGs job is PRESIDENT
TURNER     DBA       TURNERs job is DBA
JAMES      DBA       JAMESs job is DBA
FORD       ANALYST   FORDs job is ANALYST
MILLER     CLERK     MILLERs job is CLERK
14 rows selected```

# substr函数

```SQL> select ename,concat(ename,job),length(ename),instr(ename,'a') from emp where substr(job,1,5)='ANALY';
ENAME      CONCAT(ENAME,JOB)   LENGTH(ENAME) INSTR(ENAME,'A')
---------- ------------------- ------------- ----------------
SCOTT      SCOTTANALYST                    5                0
FORD       FORDANALYST                     4                0 ```

# length函数

```SQL> select ename,length(ename) from emp;
ENAME      LENGTH(ENAME)
---------- -------------
SMITH                  5
ALLEN                  5
WARD                   4
JONES                  5
MARTIN                 6
BLAKE                  5
CLARK                  5
SCOTT                  5
KING                   4
TURNER                 6
JAMES                  5
FORD                   4
MILLER                 6
14 rows selected ```

# instr函数

```SQL> select ename,instr(ename,'A') from emp ;
ENAME      INSTR(ENAME,'A')
---------- ----------------
SMITH                     0
ALLEN                     1
WARD                      2
JONES                     0
MARTIN                    2
BLAKE                     3
CLARK                     3
SCOTT                     0
KING                      0
TURNER                    0
JAMES                     2
FORD                      0
MILLER                    0
14 rows selected```

```SQL> select ename,concat(ename,job),length(ename),instr(ename,'a') from emp;
ENAME      CONCAT(ENAME,JOB)   LENGTH(ENAME) INSTR(ENAME,'A')
---------- ------------------- ------------- ----------------
SMITH      SMITHCLERK                      5                0
ALLEN      ALLENDBA                        5                0
WARD       WARDDBA                         4                0
JONES      JONESMANAGER                    5                0
MARTIN     MARTINDBA                       6                0
BLAKE      BLAKEDBA                        5                0
CLARK      CLARKMANAGER                    5                0
SCOTT      SCOTTANALYST                    5                0
KING       KINGPRESIDENT                   4                0
TURNER     TURNERDBA                       6                0
JAMES      JAMESDBA                        5                0
FORD       FORDANALYST                     4                0
MILLER     MILLERCLERK                     6                0
14 rows selected ```

```SQL> select ename,lpad(ename,10,'-') from emp;
---------- --------------------
SMITH      -----SMITH
ALLEN      -----ALLEN
WARD       ------WARD
JONES      -----JONES
MARTIN     ----MARTIN
BLAKE      -----BLAKE
CLARK      -----CLARK
SCOTT      -----SCOTT
KING       ------KING
TURNER     ----TURNER
JAMES      -----JAMES
FORD       ------FORD
MILLER     ----MILLER
14 rows selected ```

# trim函数

```SQL> select trim('s' from 'sdfde') from dual;
TRIM('S'FROM'SDFDE')
--------------------
dfde

SQL> select trim('s' from 'sdsfsde') from dual;
TRIM('S'FROM'SDSFSDE')
----------------------
dsfsde

SQL> select trim('s' from 'ssdsfsde') from dual;
TRIM('S'FROM'SSDSFSDE')
-----------------------
dsfsde```