朱世武的书<SAS 编程技术>的例子很详细,现在想想基本上涵盖了一些论坛上的问题.
/*21.1.1 简单连接*/
proc sql;
select * from resdat.china, resdat.usa;
quit
/*21.1.3 内部连接*/
proc sql;
select * from resdat.china, resdat.usa
where china.level=usa.level;
quit;
/*21.1.3.1 使用表的别名*/
proc sql;
select * from resdat.china as a, resdat.usa as b
where a.level=b.level;
quit;
/*21.1.3.2 使用别名进行表的自我连接*/
proc sql;
select * from resdat.china a, resdat.china b
where a.level<b.level;
quit;
/*21.1.3.3 设定连接输出的排列顺序*/
proc sql;
select * from resdat.china a, resdat.china b
where a.level<b.level
order by a.level desc;
quit;
/*21.1.6 缺失值对连接的影响*/
/* 程序一 */
proc sql;
title ' Table A and B Joined';
select a.obs 'A-OBS', a.stkcd, b.obs 'B-OBS', b.stkcd
from a, b
where a.stkcd= b.stkcd;
/* 程序二 */
proc sql;
title ' Table Three and Four Joined';
select Three.Obs '3-OBS', Three.Fdcd, Four.Obs '4-OBS', Four.Fdcd
from Three, Four
where Three.fdcd= Four.fdcd and
three.fdcd is not missing;
/* 21.1.7 从多于两个表的数据集中查询数据 */
proc sql outobs=3;
select a.stkcd,b.lstknm,c.clpr
from resdat.sampstk a,resdat.lstkinfo b,resdat.qttndist c
where a.stkcd=b.stkcd and b.stkcd=c.stkcd and a.stkcd=c.stkcd;
quit;
/* 21.1.8.1 左外部连接 */
proc sql;
select * from resdat.china a left join resdat.usa b
on a.level=b.level;
quit;
/* 21.1.8.2 右外部连接 */
proc sql;
select * from resdat.china a right join resdat.usa b
on a.level=b.level;
quit;
/*21.1.8.3 完全外部连接*/
proc sql;
select * from resdat.china a full join resdat.usa b
on a.level=b.level;
quit;
/*21.1.9.1 与简单连接功能相同的Cross连接 */
proc sql;
select * from resdat.china cross join resdat.usa;
quit;
/*21.1.9.2 包含所有行的Union连接 */
proc sql;
select * from resdat.china union join resdat.usa;
quit;
/*21.1.9.3使用自动匹配连接的Natural连接*/
proc sql;
select * from resdat.china union join resdat.usa;
quit;
/* 21.1.10 连接使用COALESCE函数 */
Proc sql;
select a.level,a.china,coalesce(b.level,a.level),coalesce(b.usa,a.china)as usa
from resdat.china a full join resdat.usa b
on a.level=b.level;
quit;
/* 21.2.1 所有行匹配无重复值的情况 */
data merge1;
merge a b;
by code;
run;
proc print data=merge1 noobs;
title 'Table MERGE1';
run;
proc sql;
title 'Table MERGE1';
select a.code, a.manager, b.Assitant
from a, b
where a.code=b.code;
quit;
/* 21.2.2 部分行匹配无重复值的情况 */
/* 程序一 */
data merge2;
merge a b;
by code;
run;
proc print data=merge2 noobs;
title 'Table MERGE2';
run;
/* 程序二*/
proc sql;
select code,a.manager,b.assistant
from a natural full join b;
quit;
/* 21.2.3有重复值的情况 */
/*程序一*/
data merge3;
merge a b;
by code;
run;
proc print data=merge3 noobs;
title 'Table MERGE3';
run;
/* 程序二*/
Proc sql;
Title 'Table Merge3';
Select a.code, a.manager, b.assistant
From a full join b
On a.code=b.code;
quit;
/* 21.3.1 产生单个值的子查询 */
Proc sql;
Title 'Which Manager has the same code as Assistant Chen';
Select *
From a
Where code eq (select code from b where assistant='Chen');
Quit；
/* 21.3.2 产生多个值的子查询 */
Proc sql;
select stkcd,lstknm,lstdt from resdat.lstkinfo
where stkcd in (select stkcd from resdat.sampstk);
quit;
/* 21.3.3 混合子查询 */
proc sql;
select stkcd,yrret from resdat.yrret a
where (select stktype from resdat.lstkinfo b
where a.stkcd=b.stkcd)='A'
and '1jan2005'd<=date<='31dec2005'd;
quit;
/* 21.3.5 子查询的多重嵌套 */
Proc sql;
select stkcd,yrret from resdat.yrret a
where stkcd in (select stkcd from resdat.sampstk b
where stkcd in(select stkcd from resdat.lstkinfo c
where c.stktype='A'))
and '1jan2005'd<=date<='31dec2005'd;
quit;
/*21.3.6 在JOIN连接中使用子查询*/
proc sql;
select a.id,b.id,sqrt((a.x-b.x)**2+(a.y-b.y)**2)as dist from point a,point b
where a.id lt b.id and
calculated dist=(select min(sqrt((c.x-d.x)**2+(c.y-d.y)**2))
from point c,point d
where c.id lt d.id);
quit;
/*21.5.2 由多个查询产生非重复观测 (UNION算符)*/
/*程序一*/
proc sql;
title 'A UNION B';
select * from A
union
select * from B;
quit;
/* 程序二 */
proc sql;
title 'A UNION ALL B';
select * from A
union all
select * from B;
quit;
/*21.5.3 产生只属于第一个查询的观测(EXCEPT算符)*/
/*程序一*/
proc sql;
title 'A EXCEPT B';
select * from A
except
select * from B;
quit;
/*程序二*/
proc sql;
title 'A EXCEPT ALL B';
select * from A
except all
select * from B;
/*21.5.4 从多个查询中产生公共部分 (INTERSECT算符)*/
proc sql;
title 'A INTERSECT B';
select * from A
intersect
select * from B;
/*21.5.5 直接连接查询结果 (OUTER UNION算符)*/
/*程序一*/
proc sql;
title 'A OUTER UNION B';
select * from A
outer union
select * from B;
/*程序二*/
proc sql;
title 'A OUTER UNION CORR B';
select * from A
outer union corr
select * from B;
/* 21.5.6 特殊的查询合并方式 */
proc sql;
title 'A EXCLUSIVE UNION B';
(select * from A
except
select * from B)
union
(select * from B
except
select * from A);