I Have to find the percentage difference between two numbers.
i am using the formula A-B/(A+B/2)
I.e
select round( ( A-B)/(A+B/2)) from dual;
where a and b are two numbers. Now if a and b is 0 then the divisor comes as zero. In this case what can be done to avoid error ? what is the percentage difference between two equal numbers or 0 ?
Related
I'm trying to do something really quite basic to calculate a kind of percentage between two columns in Redshift. However, when I run the query with an example the result is simply zero because the decimals are not being covered.
code:
select 1701 / 84936;
Output:
I tried :
select cast(1701 / 84936 as numeric (10,10));
but the result was 0.0000000000.
How could I solve this silly thing?
It is integer division. Make sure that at least one argument is: NUMERIC(accurate data type)/FLOAT(caution: it's approximate data type):
/ division (integer division truncates the result)
select 1701.0 / 84936;
-- or
SELECT 1.0 * 1701 / 84936;
-- or
SELECT CAST(1701 AS NUMERIC(10,4))/84936;
DBFiddle Demo
When mixing data types the order counts
Note that the order of the elements in a math expression counts for the data type of the result.
Let's assume that we intend to calculate the percentage unit_sales/total_sales where both columns (or numbers) are integers.
See and try with this code here.
-- Some dummy table
drop table if exists sales;
create table sales as
select 3 as unit_sales, 9 as total_sales;
-- The calculations
select
unit_sales/total_sales*100, --> 0 (integer)
unit_sales/total_sales*100.0, --> 0.0 (float)
100.0*unit_sales/total_sales --> 33.3 (float and expected result)
from sales;
The output
0 | 0.0 | 33.33
The first column is 0 (integer) because of 3/9=0 in an integer division.
The second column is 0.0 because SQL first got the integer 0 (3/9), and later, SQL converts it to float in order to perform the multiplication by 100.0.
The expected result.
The non-integer 100.0 at the beginning of the expression force a non-integer calculation.
just a simple question but somehow I can't find an answer here.
I have two columns (A and B). Both contains numbers with zeros and null. I would like to get a division one by the other to get information about the ratio between each single row but I am getting ORA-01476.
I know the divisior is equal to zero but I would like to get in this row a number and not an error for whole query
A B
1 5
2 Null
3 0
NULL 3
0 4
4
I am using sql developer.
If you divide a number by zero you get an error, because the answer to such division is undefined. SQL, however, has a value for undefined: NULL. So make the result NULLinstead:
select a, b, case when b = 0 then null else a / b end as ratio
from mytable;
or
select a, b, a / case when b = 0 then null else b end as ratio
from mytable;
This is standard SQL and works in Oracle as well as in about every other RDBMS. Oracle also provides the function NULLIF as a shorter way to write the expression in the second query.
You can use nullif to return null instead of raising an error:
select A / nullif(B, 0) as division
from YourTable
If your numbers are stored as varchar, cast them to numbers before using them:
select to_number(A) / nullif(to_number(B), 0) as division
from YourTable
I want to get sum of data but I am getting wrong result
Example 1
Example 2
Result when doing sum
AS you can see from Example 1 - where p_key is 11020145101617761 and LC_Amount is 8.4 , 168 , -176.4 the sum of this is 0
similarly in Example 2 - where p_key is 1102014510615767 and LC_amount is
-571067.53, 543873.84 , 27193.69 the sum of this is also 0
but in the result when I do group by with p_key , I am not getting 0
I don't understand what is the reason behind this.
It's an example of IEEE-754 rounding errors. Note the numbers are all very close to zero, but juuuuuust off, see the exponent.
Wrap your SUM in ROUND():
SELECT ROUND( SUM( LC_Amount ), 10 )
...should do it.
This occurs because float is not true exact numeric type.
Try to use DECIMAL(10,2) type to avoid round errors.
There is a lot info about float type in the web.
Here is my code
select len(cast(code as float)),code
from tbl1
where code is not null
and this is the output:
I want a count of digits in the code column.
I don't understand why the last one is counted as 12 and not 8?
Cast it as an int instead:
select len(cast(code as int)), code
from tbl1
where code is not null;
Presumably, some sort of decimal values are getting counted.
Get the number's power of 10 and add 1. This works either if ints or reals to count the number of digits of the whole number part (note using LOG10 only works on positive numbers so I have applied ABS to get around this issue, may not be required for your data):
SELECT code, CASE WHEN Number = 0 THEN 1
ELSE FLOOR(LOG10(ABS(code))) + 1 AS NDigits
FROM tbl1
I was working on a query today which required me to use the following to find all odd number ID values
(ID % 2) <> 0
Can anyone tell me what this is doing? It worked, which is great, but I'd like to know why.
ID % 2 is checking what the remainder is if you divide ID by 2. If you divide an even number by 2 it will always have a remainder of 0. Any other number (odd) will result in a non-zero value. Which is what is checking for.
For finding the even number we should use
select num from table where ( num % 2 ) = 0
As Below Doc specify
dividend % divisor
Returns the remainder of one number divided by another.
https://learn.microsoft.com/en-us/sql/t-sql/language-elements/modulo-transact-sql#syntax
For Example
13 % 2 return 1
Next part is <> which denotes Not equals.
Therefor what your statement mean is
Remainder of ID when it divided by 2 not equals to 0
Be careful because this is not going to work in Oracle database. Same Expression will be like below.
MOD(ID, 2) <> 0
ID % 2 reduces all integer (monetary and numeric are allowed, too) numbers to 0 and 1 effectively.
Read about the modulo operator in the manual.
In oracle,
select num from table where MOD (num, 2) = 0;
dividend % divisor
Dividend is the numeric expression to divide. Dividend must be any expression of integer data type in sql server.
Divisor is the numeric expression to divide the dividend. Divisor must be expression of integer data type except in sql server.
SELECT 15 % 2
Output
1
Dividend = 15
Divisor = 2
Let's say you wanted to query
Query a list of CITY names from STATION with even ID numbers only.
Schema structure for STATION:
ID Number
CITY varchar
STATE varchar
select CITY from STATION as st where st.id % 2 = 0
Will fetch the even set of records
In order to fetch the odd records with Id as odd number.
select CITY from STATION as st where st.id % 2 <> 0
% function reduces the value to either 0 or 1
It's taking the ID , dividing it by 2 and checking if the remainder is not zero; meaning, it's an odd ID.
<> means not equal. however, in some versions of SQL, you can write !=