SQL> select ‘My Name Is ”Ma Yu Ping”’ names from dual;
NAMES
———————————————-
My Name Is ‘Ma Yu Ping’
SQL> select ‘My Name Is "Ma Yu Ping"’ names from dual;
My Name Is "Ma Yu Ping"
在Oracle中，single-quote(‘)是一個表示字元串的關鍵字。是以在字元串中用兩個”表示一個實際的單引号字元。所有才會有了上面第一條SQL的’My Name Is ”Ma Yu Ping”’ 。雙引号“被識别為一個實際的的字元串，第二條sql中的雙引号不用括引。其實Oracle提供了一個Q-quote的表達式，用來簡化SQL或PLSQL中字元串的表示。
SQL> select q’[My Name Is "Ma Yu Ping"]‘ names from dual;
SQL> select q’[My Name Is 'Ma Yu Ping']‘ names from dual;
文法很簡單，必須将要表示的字元串用一對特殊字元括起來，這對字元必須一緻。
SQL> select q’[My Name Is 'Ma Yu Ping'|' names from dual;
ERROR:
ORA-01756: 引号内的字元串沒有正确結束
SQL> select q'|My Name Is 'Ma Yu Ping'|' names from dual;
----------------------------------------------
My Name Is 'Ma Yu Ping'
常用簡化的寫法，比如一個where c='d'的産量表達式的表示方法。
SQL> select 'where c=''d''' from dual; －－老的寫法
'WHEREC=''D'''
----------------------
where c='d'
SQL> select 'where c='d'' from dual; －－原則的寫法受’表達式的影響出錯
select 'where c='d'' from dual
*
第 1 行出現錯誤:
ORA-00923: FROM keyword not found where expected
SQL> select q'[where c='d']‘ from dual; －－使用q-quote表達式的寫法
Q’[WHEREC='D']‘
———————-
where c=’d’
SELECT Q'[I'm a boy,my name is 'david']' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'(I'm a boy,my name is 'david')' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'{I'm a boy,my name is 'david'}' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'|I'm a boy,my name is 'david'|' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'aI'm a boy,my name is 'david'a' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'2I'm a boy,my name is 'david'2' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'@I'm a boy,my name is 'david'@' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'*I'm a boy,my name is 'david'*' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'#I'm a boy,my name is 'david'#' FROM DUAL; --結果：I'm a boy,my name is 'david'
SELECT Q'[[@#$%^&*~?/" ']]' FROM DUAL; --結果：[@#$%^&*~?/" ']
