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本人完全是刚刚接触IT网上的很多教程都看不懂-.-
decode(a,b,c,d,e,.....)如果a=b,则输出c,a=d,则输出e,否则....
e.g select decode("a","a","1","b","2","3") from dual
"a"="a" 输出1
select decode("b","a","1","b","2","3") from dual
"b"!="a" "b"="b" 输出2
select decode("c","a","1","b","2","3") from dual
"c"!="a" "c" !="b" 输出3
就是相当于变形了的if..else..语句 参考技术A decode(a,b,c,d,e,.....)
如果a=b,则输出c,a=d,则输出e,否则....
e.g
select
decode("a","a","1","b","2","3")
from
dual
"a"="a"
输出1
select
decode("b","a","1","b","2","3")
from
dual
"b"!="a"
"b"="b"
输出2
select
decode("c","a","1","b","2","3")
from
dual
"c"!="a"
"c"
!="b"
输出3
就是相当于变形了的if..else..语句 参考技术B decode(a,b,c,d,e,.....)
如果a=b,则输出c,a=d,则输出e,否则....
e.g
select
decode("a","a","1","b","2","3")
from
dual
"a"="a"
输出1
select
decode("b","a","1","b","2","3")
from
dual
"b"!="a"
"b"="b"
输出2
select
decode("c","a","1","b","2","3")
from
dual
"c"!="a"
"c"
!="b"
输出3
就是相当于变形了的if..else..语句
PLSQL Developer 13安装教程
1:双击安装包进行安装。点击“next”。
2:点击“w accept the termis...”同意条款,并点击“next”,进行下一步。
3:点击“enthr license information”,点击“next”。
4:在注册框中分别填入下载的信息
product code: 4vkjwhfeh3ufnqnmpr9brvcuyujrx3n3le
serial Number:226959
password: xs374ca
5:选择安装模式,默认就好。
6:点击“install”开始进行安装。
7:等待软件安装完成。
8:软件安装完成后,点击“finish”。
9:打开汉化包,选择“Chinese”进行安装,选择好软件安装位置。如果你没有修改软件安装位置,默认是“"C:Program FilesPLSQL Developer 13”。
10:点击蓝色勾进行下一步。
11:点击“绿色对勾”进行下一步。
12:等待软件汉化完成。
13:完成后打开软件。软件界面显示为中文。
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