应该可以对指定字段用case语句进行替换

如case a when '' 替换为表中另一字段

when 'ss'

else

记得我用过一个不同的做法，等我找一下！

proc sql ;

create table ab as

select

*

from a ina ,b inb

where ina.unikey=ina.unikey;

quit;

[此贴子已经被作者于2007-2-9 20:21:19编辑过]

that sql is the same as following code.

data ab;

merge a (in = ina )

b (in = inb );

by unikey ;

if a and b ;

run;

You have two ways to do it:

1. Use 'case' function to create a new variable, 'case' is really similar like 'if ... then' in your datastep.

2. Use 'coalesce' with OUTER JOINS (full join, left join, right join) operations:

coalesce (a.id, 0) will change all missing values or unmatched values of a.id as 0.

coalesce (b.id, 9999) will change all unmatched or missing value of b.id as 9999.

data a;

input id age;

cards;

run;

data b;

input id gender $;

cards;

run;

***METHOD 1****;

***MATHOD 2****;

proc sql;

select a.*, b.gender, coalesce(a.id, 0) as ina, coalesce (b.id,9999) as inb

from a full join b

quit;

[此贴子已经被作者于2007-2-23 5:33:31编辑过]