Oracle PL/SQL/Char Functions/LTRIM — различия между версиями

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Текущая версия на 09:58, 26 мая 2010

LTRIM("ABCBCA12345", "ABC")

  
SQL>
SQL> SELECT LTRIM("ABCBCA12345", "ABC")
  2  FROM   DUAL;
LTRIM
-----
12345




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LTRIM and RTRIM

  
SQL>
SQL> CREATE TABLE old_item (
  2       item_id   CHAR(20),
  3       item_desc CHAR(25)
  4       );
Table created.
SQL>
SQL> INSERT INTO old_item VALUES("LA-101", "Can, Small");
1 row created.
SQL> INSERT INTO old_item VALUES("LA-102", "Can, Large");
1 row created.
SQL> INSERT INTO old_item VALUES("LA-103", "Bottle, Small");
1 row created.
SQL> INSERT INTO old_item VALUES("LA-104", "Bottle, Large");
1 row created.
SQL> INSERT INTO old_item VALUES("NY-101", "Box, Small");
1 row created.
SQL> INSERT INTO old_item VALUES("NY-102", "Box, Large");
1 row created.
SQL> INSERT INTO old_item VALUES("NY-103", "Shipping Carton, Small");
1 row created.
SQL> INSERT INTO old_item VALUES("NY-104", "Shipping Carton, Large");
1 row created.
SQL>
SQL> SELECT "Item  " ||
  2         item_id ||
  3         " is described as a " ||
  4         item_desc ||
  5         "."  "Item Description Sentence"
  6  FROM   old_item;
Item Description Sentence
-----------------------------------------------------------------------
Item  LA-101               is described as a Can, Small               .
Item  LA-102               is described as a Can, Large               .
Item  LA-103               is described as a Bottle, Small            .
Item  LA-104               is described as a Bottle, Large            .
Item  NY-101               is described as a Box, Small               .
Item  NY-102               is described as a Box, Large               .
Item  NY-103               is described as a Shipping Carton, Small   .
Item  NY-104               is described as a Shipping Carton, Large   .
8 rows selected.
SQL>
SQL>
SQL>
SQL> drop table OLD_ITEM;
Table dropped.
SQL>
SQL>



LTRIM function removes leading characters

 
SQL>
SQL> --LTRIM function removes leading characters
SQL>
SQL> SELECT LTRIM("ST" , "STEVENS") AS TRIM FROM Dual;
T
-

SQL>



LTRIM("OPS$SPORANO", "OPS$")

  
SQL>
SQL> SELECT LTRIM("OPS$SPORANO", "OPS$")
  2  FROM   DUAL;
LTRI
----
RANO




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Ltrim: removes a set of characters from the left of a string

 
SQL>
SQL> -- Ltrim: removes a set of characters from the left of a string.
SQL>
SQL>
SQL> -- LTRIM stands for "left trim."
SQL> -- The general format for this function is:
SQL>
SQL> -- LTRIM(string, characters_to_remove)
SQL>
SQL> SELECT LTRIM("...Mitho", ".") FROM dual;
LTRIM
-----
Mitho
SQL>



select """ || ltrim(ome String" ) || """ "A String"

  
SQL>
SQL> select """ || ltrim( "    Some String" ) || """ "A String" from dual;
A String
-------------
"Some String"
1 row selected.
SQL>
SQL> --



Trim letter S from both sides

    
SQL>
SQL> create table emp
  2  ( empno      NUMBER(4)    constraint E_PK primary key
  3  , ename      VARCHAR2(8)
  4  , init       VARCHAR2(5)
  5  , job        VARCHAR2(8)
  6  , mgr        NUMBER(4)
  7  , bdate      DATE
  8  , sal       NUMBER(6,2)
  9  , comm       NUMBER(6,2)
 10  , deptno     NUMBER(2)    default 10
 11  ) ;
Table created.
SQL> insert into emp values(1,"Tom","N",   "Coder", 13,date "1965-12-17",  800 , NULL,  20);
1 row created.
SQL> insert into emp values(2,"Jack","JAM", "Tester",6,date "1961-02-20",  1600, 300,   30);
1 row created.
SQL> insert into emp values(3,"Wil","TF" ,  "Tester",6,date "1962-02-22",  1250, 500,   30);
1 row created.
SQL> insert into emp values(4,"Jane","JM",  "Designer", 9,date "1967-04-02",  2975, NULL,  20);
1 row created.
SQL> insert into emp values(5,"Mary","P",  "Tester",6,date "1956-09-28",  1250, 1400,  30);
1 row created.
SQL> insert into emp values(6,"Black","R",   "Designer", 9,date "1963-11-01",  2850, NULL,  30);
1 row created.
SQL> insert into emp values(7,"Chris","AB",  "Designer", 9,date "1965-06-09",  2450, NULL,  10);
1 row created.
SQL> insert into emp values(8,"Smart","SCJ", "Coder", 4,date "1959-11-26",  3000, NULL,  20);
1 row created.
SQL> insert into emp values(9,"Peter","CC",   "Designer",NULL,date "1952-11-17",  5000, NULL,  10);
1 row created.
SQL> insert into emp values(10,"Take","JJ", "Tester",6,date "1968-09-28",  1500, 0,     30);
1 row created.
SQL> insert into emp values(11,"Ana","AA",  "Coder", 8,date "1966-12-30",  1100, NULL,  20);
1 row created.
SQL> insert into emp values(12,"Jane","R",   "Manager",   6,date "1969-12-03",  800 , NULL,  30);
1 row created.
SQL> insert into emp values(13,"Fake","MG",   "Coder", 4,date "1959-02-13",  3000, NULL,  20);
1 row created.
SQL> insert into emp values(14,"Mike","TJA","Manager",   7,date "1962-01-23",  1300, NULL,  10);
1 row created.
SQL>
SQL>
SQL> select ename
  2  ,      ltrim(ename,"S") as ltrim_s
  3  ,      rtrim(ename,"S") as rtrim_s
  4  from   emp
  5  where  deptno = 20;
ENAME    LTRIM_S  RTRIM_S
-------- -------- --------
Tom      Tom      Tom
Jane     Jane     Jane
Smart    mart     Smart
Ana      Ana      Ana
Fake     Fake     Fake
SQL>
SQL>
SQL> drop table emp;
Table dropped.