1：獲取數(shù)據(jù)集前幾行觀測

proc sql outobs=5; *outobs選項(xiàng)只限制顯示的行數(shù)，并不限制讀入的行數(shù). inobs=選項(xiàng)可以限制讀入的行數(shù);select * from sashelp.class; quit;data res;set sashelp.class (obs=5); run;

2：Eliminating Duplicate Rows from Output ?

DISTINCT ：?applies to all columns, and only those columns, that are listed in the SELECT clause.

注意這里一個(gè)細(xì)節(jié)，distinct的變量會(huì)默認(rèn)排序

proc sql; select distinct flightnumber, destination /*distinct只能跟在select后*/ from sasuser.internationalflights; quit;

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3：條件運(yùn)算符

?To create a negative condition, you can precede any of these conditional operators, except for ANY and ALL, with the NOT operator.?

3.1：BETWEEN value-1 AND value-2 ?（ between or equal to 兩端的value是被包括進(jìn)去的）

To select rows based on a range of numeric or character values（value可以使數(shù)字也可以是字符），When specifying the limits for the range of values, it is not necessary to specify the smaller value first. （value-1/2的大小無要求）

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3.2:Using the CONTAINS or Question Mark (?) Operator to Select a String ?

sql-expression CONTAINS/? sql-expression?

where sql-expression is a character column, string (character constant), or expression(contain某些東西的列是字符型)

proc sql outobs=10; select name from sasuser.frequentflyers where name contains 'ER'; quit;

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3.3:IN Operator to Select Values from a List ?

column IN (constant-1 <, . . . constant-n>)?

constant-1 and constant-n represent a list that contains one or more specific values.(括號(hào)中的常量個(gè)數(shù)大于等于1)

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3.4：?IS MISSING or IS NULL Operator to Select Missing Values ?

To select rows that contain missing values, both character and numeric, use the IS MISSING or IS NULL operator. These operators are interchangeable. ?

（字符型和數(shù)值型缺失都可檢驗(yàn)，這兩個(gè)符號(hào)是等價(jià)的）

where column = ' '; where column = .;分別只能檢驗(yàn)字符型和數(shù)值型缺失。

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3.5：?LIKE Operator to Select a Pattern?

column LIKE 'pattern' ?

underscore ( _ ) ?any single character?

percent sign (%) ?any sequence of zero or more characters

proc sql; select ffid, name, address from sasuser.frequentflyers where address like '% P%PLACE'; *空格也包含在字符串中; quit;

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3.6：Using the Sounds-Like (=*) Operator to Select a Spelling Variation?

The sounds-like (=*) operator uses the SOUNDEX algorithm to compare each value of a column (or other sql-expression) with the word or words (or other sql-expression) that you specify.

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3.7：Subsetting Rows by Using Calculated Values （sas特有的，不是標(biāo)準(zhǔn)sql中的）

sas編譯時(shí)，先執(zhí)行where,如果不用calculated那么就會(huì)報(bào)錯(cuò)說沒有total這個(gè)變量，加上后會(huì)在新生成的變量中查找。

proc sql outobs=10; select flightnumber, date, destination, boarded + transferred + nonrevenue as Total,
　　　　　　calculated Total/2 as half from sasuser.marchflights where calculated total < 100; /*想要使用新生成的列的時(shí)候，需要加上calculated關(guān)鍵字,having要加 order by 不用加*/

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3.8：Using the ANY Operator?

where dateofbirth < any ? (subquery...) ? ? ? ? ? ? ?

<any equal to max() ? ?比如，子查詢返回20 、30、 40，那么，外查詢選擇所有<40的記錄

>any equal to min()　 ?比如，子查詢返回20 、30、 40，那么，外查詢選擇所有>20的記錄

=any equal to in

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3.9：Using the ALL Operator?

all和any相反

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3.10：exsits 、not exsits

對于exsits，為真的話就輸出，假的就不輸出。

對于not exsits相反。

/*需求，選擇是員工又是經(jīng)常單獨(dú)飛行的人姓名*/
proc sql; title 'Frequent Flyers Who Are Employees';
select name
from sasuser.frequentflyers
where exists
(select * from sasuser.staffmaster
where name=trim(lastname)||', '||firstname)
order by name;
quit;

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4、NOEXEC 、VALIDATE;

相同點(diǎn)：這兩個(gè)關(guān)鍵字都有使程序不執(zhí)行，只進(jìn)行語法檢查的效果！

不同點(diǎn)：validate只對緊跟其后的select語句有效，noexec對真?zhèn)€sql過程有效

proc sql noexec; select empid, jobcode, salary from sasuser.payrollmaster where jobcode contains 'NA' order by salary; quit;

proc sql;
validate
select empid, jobcode, salary
　　from sasuser.payrollmaster
　　where jobcode contains 'NA'
　　order by salary;
quit;

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?4.1 feedback,在列比較多，我用來查看列名。。。。然后復(fù)制粘貼我想要的名字。。。

*options fullstimer=on;*run; proc sql feedback; select * from sashelp.class; NOTE: 語句變換為:select CLASS.Name, CLASS.Sex, CLASS.Age, CLASS.Height, CLASS.Weightfrom SASHELP.CLASS;quit;

?4.2Count

只計(jì)算非缺失值

轉(zhuǎn)載于:https://www.cnblogs.com/yican/p/4079283.html

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