SQL query to extract a number and its decimal variations [closed] - sql

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I have column with all kinds of numbers, I am specifically trying to extract numbers that have either
555
or
555.xx
or
555.x
The output should look like this
555
555.1
555.5
555.9
555.58
555.22
.
.
IE I need an sql query that will return the rows that have just the number 555 with any decimal fraction from my column of arbitrary numbers.

Answer 1

You can try LIKE statement
WHERE Col LIKE '555.%'
OR Col = '555'

Answer 2

As a fast approach I would do
CAST((ValueOfTable * 100.00) AS DECIMAL(18, 2))
my table name is Diagnosis and the column name is code, where should I
add the table name and column name in this code ?
In your situation:
SELECT
CAST((code * 100.00) AS DECIMAL(18, 2))
FROM Diagnosis ;
I'm expecting this to be an integer. You can find out executing:
\d Diagnosis ;
one of the output lines should look similar to
(...)
code | integer |
(...)

Answer 3

Assuming the column contains numbers (not as string/varchar), search for "number>=555 and number<556". This would give you 555, 555.01... etc.

Answer 4

If the CODE column is a varchar (which I understand it to be from your comments, but you might want clarify that in the question body itself), and can/does contain values that are not numbers, then you have to be very careful about using functions which only accept a number.
With this sample data, you can see that having one value that can't be cast to a number will cause the whole query to error out.
select * from diagnosis order by code;
CODE
-----------
555
555.0
555.43
555.99
Not a Num
(5 rows)
select code + 1 from diagnosis;
ERROR: pg_atoi: error in "Not a Num": can't parse "Not a Num"
The usual solution to this is to either match the column value via regular expression, or use a function to test whether or now the value in each row is a number.
Here are two solutions, each of which depends on a function that is provided with Netezza, but not necessarily installed by default. Your administrator can install these for you.
The first uses the regexp_instr from the SQL Extension Toolkit. Here you use a regular expression to match the values you want without having to do an actual CAST (implicit or explicit) to a numeric.
SELECT code FROM diagnosis
WHERE regexp_instr(code, '^555(\.\d+)?$') > 0;
CODE
--------
555
555.0
555.43
555.99
(4 rows)
The second solution, which is a bit more involved, uses the isnumeric() UDF provided as part of the Netezza InDatabase Analytics package (in the /nz/extensions/nz/nzlua/examples directory when installed), to test whether the CODE column is a numeric before casting CODE as a numeric.
SELECT code
FROM (
SELECT code
FROM diagnosis
WHERE isnumber(code)
)
foo
WHERE floor(code::NUMERIC(38,2)) = 555;
CODE
--------
555
555.0
555.43
555.99
(4 rows)
Both of these functions are included with Netezza, but both require installation by your administrator before you can use them. In each case this is a simple task for the administrator, although they may not be aware of their availability.