# General Computations

Read（402） Label: general computation,

This chapter lists code examples about functions of general computations, including IS NULL/NVL/COALESCE, CAST/CONVERT, CASE/DECODE, AND/OR/NOT/<>, LIKE, COUNT/SUM/AVG/MAX/MIN, and IN/EXISTS.

## IS NULL/NVL/COALESCE

 A 1 =demo.query("select EID,NAME,STATE,GENDER,BIRTHDAY, HIREDATE,DEPT, SALARY from EMPLOYEE") 2 =A1.select(DEPT!=null) Not null 3 =A1.select(DEPT ==null) Null 4 =demo.query("select NAME,UNITPRICE,QUANTITY from RECEIPT") 5 =A4.(NAME).ifn() The first non-null member

## CAST/CONVERT

 A 1 =date("1983-09-12") Convert string to date 2 =string(A1,"yyyyMMdd") Convert date to string 3 =int("5") Convert string to integer 4 =string(5) Convert integer to string 5 =decimal(A3) Convert integer to big decimal 6 =ifnumber(A5) Judge if A5 is a number 7 =float("234") Convert string to float

## CASE/DECODE

 A 1 1 2 =case(A1,1,"ClassOne",2,"ClassTwo","ClassThree") 3 =if(A1==1, "ClassOne", A1==2,"ClassTwo","ClassThree")

## AND/OR/NOT, <>

 A 1 =demo.query("select * from SALES") 2 =A1.select(CLIENT=="PWQ" || CLIENT=="QUICK") OR 3 =A1.select(AMOUNT>5000 && AMOUNT<10000) AND 4 =A1.select(!(CLIENT=="TRADH")) NOT 5 =A1.select(CLIENT!="TRADH") <>

## LIKE

 A 1 =demo.query("select * from SALES") 2 =A1.select(like(CLIENT,"*AY*"))

## COUNT/SUM/AVG/MAX/MIN

 A 1 =demo.query("select * from SALES") 2 =A1.sum(AMOUNT) 3 =A1.count() 4 =A1.avg(AMOUNT) 5 =A1.max(AMOUNT) 6 =A1.min(AMOUNT)

## IN/EXISTS

 A 1 [1,3,5,7,9] 2 =demo.query("select * from EMPLOYEE") 3 =A2.select(A1.pos(EID)>0) IN 4 [English,Math] 5 =demo.query("select * from SCORES where CLASS='Class one'") 6 =A5.select(SCORE>75).group(STUDENTID) 7 =A6.select(~.(SUBJECT).pos(A4)!=null) EXISTS 8 =A7.(STUDENTID)