PL/SQLѧϰ±Ê¼ÇÈý
1.Ìõ¼þ¿ØÖÆ
1.1 if .. then .. end if
if Ìõ¼þ then
Óï¾ä¶Î£»
end if;
1.2 if .. then .. else .. end if
if Ìõ¼þ then
Óï¾ä¶Î£»
else
Óï¾ä¶Î£»
end if;
1.3 ifǶÌ×
2.Ñ»·¿ØÖÆ
2.1 loop .. exit .. end loop
loop
Ñ»·Óï¾ä¶Î;
if Ìõ¼þÓï¾ä then
Óï¾ä¶Î;
exit;
else
Óï¾ä¶Î;
end if
end loop;
2.2 loop .. exit .. when .. end loop
loop
Óï¾ä¶Î;
exit when Ìõ¼þÓï¾ä;
end loop;
2.3 while .. loop .. end loop
while Ìõ¼þ loop
Óï¾ä¶Î;
end loop;
2.4 for .. in .. loop.. end
for Ñ»·±äÁ¿ in [reverse] Ñ»·Ï½ç..Ñ»·ÉϽç loop
Óï¾ä¶Î;
end loop;
×¢Ò⣺reverse±íʾ´ÓºóÍùÇ°Ñ»·£¬Ñ»·ÉÏϽ粻±ä
ʾÀý£º
set serveroutput on
declare
i integer:=0;
begin
for i in reverse 1..10 loop
dbms_output.put_line('i 掙朧' || to_char(i));
end loop;
end;
Êä³ö˳Ðò£º10 9 8 7 6 5 4 3 2 1
Ïà¹ØÎĵµ£º
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µÚÒ»²½£º
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select sum(quantity) total ,price_water,price_pollute from pay_water where time_pay >='2010-02-01 00:00:00.000' and time_pay <'2010-02-28 23:59:59.000'
group by price_water,price_pollute
µÚ¶þ²½ ......
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1¡¢ISNULL ( check_expression , replacement_value )
²ÎÊý
check_expression
½«±»¼ì²éÊÇ·ñΪ NULLµÄ±í´ïʽ¡£check_expression ¿ÉÒÔÊÇÈκÎÀàÐ͵ġ£
replacement_valueÔÚ check_expressionΪNULLʱ½«·µ»ØµÄ±í´ïʽ¡£replacement_value ±ØÐëÓë check_expresssion ¾ßÓÐÏàͬµÄÀàÐÍ¡£
·µ»ØÀàÐÍ
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