IF语句的使用
A.基本的IF条件语句：
基本语法:
程序代码
IF THEN
END IF;
Example:
程序代码
结果：
x is less than10
PL/sql procedure successfully completed
B.IF - ELSE 语句
基本语法：
程序代码
IF THEN
ELSE
END IF;
Example:
程序代码
DECLARE
x NUMBER(3) := 10;
BEGIN
IF x < 10 THEN
dbms_output.put_line('X is less than 10');
ELSE
dbms_output.put_line('X is not less than 10');
END IF;
END;
/
结果：
X is not less than 10
PL/sql procedure successfully completed
C:IF - ELSIF - ELSE 语句
基本语法:
程序代码
IF THEN
ELSIF THEN
ELSIF THEN
ELSE
END IF;
Example:
程序代码
set serveroutput on
DECLARE
x NUMBER(3) := 47;
BEGIN
IF x < 10 THEN
dbms_output.put_line('X is less than 10');
ELSIF x = 10 THEN
dbms_output.put_line('X is equal to 10');
ELSIF x < 100 THEN
dbms_output.put_line('X is between 11 and 99');
ELSE
dbms_output.put_line('X is greater than 99');
END IF;
END;
/
结果：
X is between 11 and 99
PL/sql procedure successfully completed
D:与NULL值比较处理
Example:
程序代码
declare v NUMBER; begin if v = 1 then DBMS_OUTPUT.put_line('Equal to 1'); elsif v!= 1 then DBMS_OUTPUT.put_line('Not equal to 1'); elsif v = v then DBMS_OUTPUT.put_line('Equal to itself'); else DBMS_OUTPUT.put_line('Undefined result'); end if; v:=v+1; DBMS_OUTPUT.put_line('New value: <'||v||'>'); end; /
