How to convert a hash string to an integer in Snowflake? - sql

I'm trying to get a hash of a decimal value and convert it to an integer. But the query results in the following error:
Numeric value 'b902cc4550838229a710bfec4c38cbc7eb11082367a409df9135e7f007a96bda' is not recognized
SELECT (CAST(sha2(TO_VARCHAR(ABS(12.5)), 256) AS INTEGER) % 100) AS temp_value
What is the correct way to convert a hash string to an integer in Snowflake?
I can not use any user defined functions. And have to go with Snowflake native functions.

The hash value contains alphabetic character so it will throw an error
SELECT --(CAST(
sha2(
TO_VARCHAR(
ABS(12.5)), 256)-- AS INTEGER) % 100)
AS temp_value;

You need to convert the hex value from the hash encoding to be int.
I've not been able to find a function built into Snowflake that does this, but if you have a look in the following link, it will explain how to create a javascript function to do the conversion for you:
https://snowflakecommunity.force.com/s/article/faq-does-snowflake-have-a-hex-to-int-type-function
If you use the function in the link, then your code becomes something like this:
SELECT (CAST(js_hextoint(sha2(TO_VARCHAR(ABS(12.5)), 256)) AS INTEGER) % 100) AS temp_value
I've not been able to test the above code I'm afraid, so there may be a bracket in the wrong place...

You have a 56 digit hexadecimal number. It's not going to fit into the maximum numeric precision of 38. You could use a floating point number, but that will lose precision.
create or replace function CONV(VALUE_IN string, OLD_BASE float, NEW_BASE float)
returns string
language javascript
as
$$
// Usage note: Loses precision for very large inputs
return parseInt(VALUE_IN, Math.floor(OLD_BASE).toString(Math.floor(NEW_BASE)));
$$;
select conv('b902cc4550838229a710bfec4c38cbc7eb11082367a409df9135e7f007a96bda', 16, 10);
--Returns 8.368282050700398e+76

For hex to integer, check Does snowflake have a ‘hex’ to ‘int’ type native function?. My guess is that most people checking this question (1k views) are looking for that.
But this specific question wants to convert a sha2 digest to integer for comparison purposes. My advice for that specific question is "don't".
That's because the hex string in the question represent the integer 83682820507003986697271120393377917644380327831689630185856829040117055843290, which is too much to handle even by Java's BigInteger.
Instead, just compare strings/binary to check if the values match or not.

Related

What to try to get BigQuery to CAST BYTES to STRING?

BigQuery Standard SQL documentation suggests that BYTE fields can be coerced into STRINGS.
We have a byte field that is the result of SHA256 hashing a field using BigQuery itself.
We now want to coerce it to a STRING, yet when we run "CAST(field_name to STRING)" we get an error:
Query Failed Error: Invalid cast of bytes to UTF8 string
What is preventing us from getting a string from this byte field? Is it surmountable? If so, what is the solution?
Below example should show you an idea
#standardSQL
WITH t AS (
SELECT SHA256('abc') x
)
SELECT x, TO_BASE64(x)
FROM t
in short - you can use TO_BASE64() for this
If you want to see the "traditional" representation of the hash in String, you have to use TO_HEX() function.
WITH table AS (
SELECT SHA256('abc') as bytes_field
)
SELECT bytes_field, TO_HEX(bytes_field) as string_field
FROM table
By default in the UI, BigQuery shows you the base64 representation but if you want to compare it with other sha256 function from other language, for example, you have to use TO_HEX()
You can try SAFE_CONVERT_BYTES_TO_STRING() function.
reference: SAFE_CONVERT_BYTES_TO_STRING

how to convert this String to Decimal

i have this String '5666,232343' and i want to convert it to Decimal, i use cast('5666,232343' as decimal(7,5)) but it returns NULL value.
Do you know why it doesn't work with CAST
Zorkolot is right. The current precision and scale that you've used is not sufficient for the value you've provided.
If you're using SQL Server 2012 or higher and you want to keep the comma in the value, then you can use the TRY_PARSE function and set a culture. It will return NULL if it encounters an error instead of not completing the statement and returning red text. This also allows you to add basic error handling to the statement, if you wanted, by getting failed conversions to return the value of zero. For example:
This is your original query (which is currently erroring) with my error handling fix:
select coalesce(try_parse('5666,232343' as decimal(7,5) using 'en-GB'),'0') as [DecimalValue]
This is the same thing as above but I've amended the decimal precision and scale so that the value is successfully converted:
select coalesce(try_parse('5666,232343' as decimal(16,6) using 'en-GB'),'0') as [DecimalValue]
This should prevent you having to perform a REPLACE either manually or by using the SQL function.
You need to cast to a decimal that can hold the value of 5666.232343.
DECIMAL(7,5) allows numbers in this format: ##.#####. The biggest number you can have then is 99.99999. You also need to take the comma out and replace it with a period:
SELECT CAST('5666.232343' as decimal(16,6)) AS [DecimalValue]
The problem is probably the comma. In some databases, some of the functions are not as internationally-sensitive as (I think) they should be. So try:
cast(replace('5666,232343', ',', '.') as decimal(7, 5))

Division in VB.NET only shows the whole number

I'm making a simple calculator code, and when I do the division I want it to show not just the whole number but the decimal number.
This is my division code:
get1.Text = Int(mygive.Text \ rate.Text)
I've also tried:
get1.Text = Int(mygive.Text / rate.Text)
I want it to show numbers like this: 2060.0891
Thanks in advance!
You need to convert the numbers to Double prior to doing the division. CDbl is an appropriate Type Conversion Function for this:
Dim answer = CDbl(mygive.Text) / CDbl(rate.Text)
get1.Text = answer.ToString()
Your Int is converting everything to whole numbers. Try converting to double.
It's showing only the whole part of the number because you're declaring an Integer, which is insufficient, as it can only store whole numbers.
You need to use the Double data type.
Also, you're attempting to apply arithmetic operations on Strings, which is invalid.
You need to convert those strings to be of the type Double before you can do / on them.
Use converting to Double/Decimal
with VB help function:
get1.Text = CDec(mygive.Text / rate.Text).ToString()
with .NET function
get1.Text = Convert.ToDecimal(mygive.Text / rate.Text).ToString()

Cleanest way to convert a `Double` or `Single` to `Integer`, without rounding

Converting a floating-point number to an integer using either CInt or CType will cause the value of that number to be rounded. The Int function and Math.Floor may be used to convert a floating-point number to a whole number, rounding toward negative infinity, but both functions return floating-point values which cannot be implicitly used as Integer values without a cast.
Is there a concise and idiomatic alternative to IntVar = CInt(Int(FloatingPointVar));? Pascal included Round and Trunc functions which returned Integer; is there some equivalent in either the VB.NET language or in the .NET framework?
A similar question, CInt does not round Double value consistently - how can I remove the fractional part? was asked in 2011, but it simply asked if there was a way to convert a floating-point number to an integer; the answers suggested a two-step process, but it didn't go into any depth about what does or does not exist in the framework. I would find it hard to believe that the Framework wouldn't have something analogous to the Pascal Trunc function, given that such a thing will frequently be needed when performing graphical operations using floating-point operands [such operations need to be rendered as discrete pixels, and should be rounded in such a way that round(x)-1 = round(x-1) for all x that fit within the range of +/- (2^31-1); even if such operations are rounded, they should use Floor(x+0.5), rather than round-to-nearest-even, so as to ensure the above property]
Incidentally, in C# a typecast from Double to Int using (type)expr notation uses round-to-zero semantics; the fact that this differs from the VB.NET behavior suggests that one or both languages is using its own conversion routines rather an explicit conversion operator included in the Framework. It would seem likely that the Framework should define a conversion operator? Does such an operator exist within the framework? What does it do? Is there a way to invoke it from C# and/or VB.NET?
After some searching, it seems that VB has no clean way of accomplishing that, short of writing an extension method.
The C# (int) cast translates directly into conv.i4 in IL. VB has no such operators, and no framework function seems to provide an alternative.
Usenet had an interesting discussion about this back in 2005 – of course a lot has changed since then but I think this still holds.
You can use the Math.Truncate method.
Calculates the integral part of a specified double-precision floating-point number.
For example:
Dim a As double = 1.6666666
Dim b As Integer = Math.Truncate(a) ' b = 1
I know this is an old case but I saw no one suggest the Math.Round() function.
Yes Math.Round takes a double and returns a double. However it returns a number that has been rounded to a whole number. It should easily and concisely convert to an integer using cInt. Would that suffice?
cInt(math.round(10000.54564)) ' = 10001
cInt(math.round(10000.49564)) ' = 10000
You may need extract the Int part of a float number:
float num = 12.234;
string toint = "" + num;
string auxil = toint.Split('.');
int newnum = Int.Parse(auxil[0]);

ISNUMERIC('07213E71') = True?

SQL is detecting that the following string ISNUMERIC:
'07213E71'
I believe this is because the 'E' is being classed as a mathmatical symbol.
However, I need to ensure that only values which are whole integers are returned as True.
How can I do this?
07213E71 is a floating number 7213 with 71 zeros
You can use this ISNUMERIC(myValue + '.0e0') to test for whole integers. Slightly cryptic but works.
Another test is the double negative myValue NOT LIKE '%[^0-9]%' which allows only digits 0 to 9.
ISNUMERIC has other issues in that these all return 1: +, -,
To nitpick: This is a whole integer. It is equivalent to 7213 * 10 ^ 71.
In the documentation it says
ISNUMERIC returns 1 when the input expression evaluates to a valid integer, floating point number, money or decimal type; otherwise it returns 0. A return value of 1 guarantees that expression can be converted to one of these numeric types.
Your number is also float (with exponential notation), therefore the only way to have ISINTEGER is to define it yourself on SQL. Read the following link.
http://classicasp.aspfaq.com/general/what-is-wrong-with-isnumeric.html
Extras:
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=59049
http://www.tek-tips.com/faqs.cfm?fid=6423
I have encountered the same problem. IsNumeric accepts "$, €, +, -, etc" as valid inputs and Convert function throws errors because of this.
Using "LIKE" SQL statement fixed my problem. I hope it'll help the others
SELECT UnitCode, UnitGUID, Convert(int, UnitCode) AS IntUnitCode
FROM [NG_Data].[NG].[T_GLB_Unit]
WHERE ISNULL(UnitType,'') <>'Department'
AND UnitCode NOT LIKE '%[^0-9]%'
ORDER BY IntUnitCode
PS: don't blame me for using "UnitCode" as nvarchar :) It is an old project :)
You have to ensure it out of the call to the database, whatever the language you work with, and then pass the value to the query. Probably the SQL is understanding that value as a string.