I need to execute a SQL query, which converts a String column to a Array and then validate the size of that array
I was able to do it easily with postgresql:
e.g.
select
cardinality(string_to_array('a$b','$')),
cardinality(string_to_array('a$b$','$')),
cardinality(string_to_array('a$b$$$$$','$')),
But for some reason trying to convert String on vertica to array is not that simple, Saw this links:
https://www.vertica.com/blog/vertica-quick-tip-dynamically-split-string/
https://forum.vertica.com/discussion/239031/how-to-create-an-array-in-vertica
And much more that non of them helped.
I also tried using:
select REGEXP_COUNT('a$b$$$$$','$')
But i get an incorrect value - 1.
How can i Convert String to array on Vertica and gets his Length ?
$ has a special meaning in a regular expression. It represents the end of the string.
Try escaping it:
select REGEXP_COUNT('a$b$$$$$', '[$]')
You could create a UDx scalar function (UDSF) in Java, C++, R or Python. The input would be a string and the output would be an integer. https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/ExtendingVertica/UDx/ScalarFunctions/ScalarFunctions.htm
This will allow you to use language specific array logic on the strings passed in. For example in python, you could include this logic:
input_list = input.split("$")
filtered_input_list = list(filter(None, input_list))
list_count = len(filtered_input_list)
These examples are a good starting point for writing UDx's for Vertica. https://github.com/vertica/UDx-Examples
I wasn't able to convert to an array - but Im able to get the length of the values
What i do is convert to Rows an use count - its not best performance wise
But with this way Im able to do also manipulation like filtering of each value between delimiter - and i dont need to use [] for characters like $
select (select count(1)
from (select StringTokenizerDelim('a$b$c','$') over ()) t)
Return 3
Related
I have, in a database, records that are serialized PHP strings that I must obfuscate emails if there are any. The simplest record is like {s:20:"pika.chu#pokemon.com"}. It is basically saying: this is a string of length 20 which is pika.chu#pokemon.com. This field can be kilobytes long with lot of emails (or none) and sometimes it is empty.
I wish I could use a SQL regular expression function to obfuscate the user part of the email while preserving the length of the string in order not to break the PHP serialization. The example email above shall be turned into {s:20:"xxxxxxxx#pokemon.com"} where the number of x matches the length of pika.chu.
Any thoughts?
Here is a more complete example of what can be found as serialized PHP:
a:4:{s:7:"locales";a:3:{i:0;s:5:"fr_FR";i:1;s:5:"de_DE";i:2;s:5:"en_US";}s:9:"publisher";s:18:"john#something.com";s:7:"authors";a:2:{i:0;s:21:"william#something.com";i:1;s:19:"debbie#software.org";}s:12:"published_at";O:8:"DateTime":3:{s:4:"date";s:26:"2022-01-26 13:05:26.531289";s:13:"timezone_type";i:3;s:8:"timezone";s:3:"UTC";}}
I tried to do it using native functions but it not worked because functions like REGEXP_REPLACE don't let you manipulate the match to get the size of it, for example.
Instead, I've created a UDF to do that:
CREATE TEMP FUNCTION hideEmail(str STRING)
RETURNS STRING
LANGUAGE js AS """
return str
.replace(/([a-zA-Z.0-9_\\+-:]*)#/g, function(txt){return '*'.repeat(txt.length-1)+"#";})
""";
select hideEmail('a:4:{s:7:"locales";a:3:{i:0;s:5:"fr_FR";i:1;s:5:"de_DE";i:2;s:5:"en_US";}s:9:"publisher";s:18:"john#something.com";s:7:"authors";a:2:{i:0;s:21:"william#something.com";i:1;s:19:"debbie#software.org";}s:12:"published_at";O:8:"DateTime":3:{s:4:"date";s:26:"2022-01-26 13:05:26.531289";s:13:"timezone_type";i:3;s:8:"timezone";s:3:"UTC";}}')
Result:
a:4:{s:7:"locales";a:3:{i:0;s:5:"fr_FR";i:1;s:5:"de_DE";i:2;s:5:"en_US";}s:9:"publisher";s:18:"****#something.com";s:7:"authors";a:2:{i:0;s:21:"*******#something.com";i:1;s:19:"******#software.org";}s:12:"published_at";O:8:"DateTime":3:{s:4:"date";s:26:"2022-01-26 13:05:26.531289";s:13:"timezone_type";i:3;s:8:"timezone";s:3:"UTC";}}
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
In my Room model, I have an attribute named available_days, which is being stored as an array.
For example:
Room.first.available_days
=> ["wed", "thurs", "fri"]
What is the best way to find all Rooms where the size of the array is equal to 3?
I've tried something like
Room.where('LENGTH(available_days) = ?', 3)
with no success.
Update: the data type for available_days is a string, but in order to store an array, I am serializing the attribute from my model:
app/models/room.rb
serialize :available_days
Can't think of a purely sql way of doing it for sqlite since available_days is a string.
But here's one way of doing it without loading all records at once.
rooms = []
Room.in_batches(of: 10).each_record do |r|
rooms << r if r.available_days.length == 3
end
p rooms
If you're using postgres you can parse the serialized string to an array type, then query on the length of the array. I expect other databases may have similar approaches. How to do this depends on how the text is being serialized, but by default for Rails 4 should be YAML, so I expect you data is encoded like this:
---
- first
- second
The following SQL will remove the leading ---\n- as well as the final newline, then split the remaining string on - into an array. It's not strictly necessary to cleanup the extra characters to find the length, but if you want to do other operations you may find it useful to have a cleaned up array (no leading characters or trailing newline). This will only work for simple YAML arrays and simple strings.
Room.where("ARRAY_LENGTH(STRING_TO_ARRAY(RTRIM(REPLACE(available_days,'---\n- ',''),'\n'), '\n- '), 1) = ?", 3)
As you can see, this approach is rather complex. If possible you may want to add a new structured column (array or jsonb) and migrate the serialized string into the a typed column to make this easier and more performant. Rails supports jsonb serialization for postgres.
I need to store an alphanumeric string in an integer column on one of my models.
I have tried:
#result.each do |i|
hex_id = []
i["id"].split(//).each{|c| hex_id.push(c.hex)}
hex_id = hex_id.join
...
Model.create(:origin_id => hex_id)
...
end
When I run this in the console using puts hex_id in place of the create line, it returns the correct values, however the above code results in the origin_id being set to "2147483647" for every instance. An example string input is "t6gnk3pp86gg4sboh5oin5vr40" so that doesn't make any sense to me.
Can anyone tell me what is going wrong here or suggest a better way to store a string like the aforementioned example as a unique integer?
Thanks.
Answering by request form OP
It seems that the hex_id.join operation does not concatenate strings in this case but instead sums or performs binary complement of the hex values. The issue could also be that hex_id is an array of hex-es rather than a string, or char array. Nevertheless, what seems to happen is reaching the maximum positive value for the integer type 2147483647. Still, I was unable to find any documented effects on array.join applied on a hex array, it appears it is not concatenation of the elements.
On the other hand, the desired result 060003008600401100500050040 is too large to be recorded as an integer either. A better approach would be to keep it as a string, or use different algorithm for producing a number form the original string. Perhaps aggregating the hex values by an arithmetic operation will do better than join ?
Is there a simple way (like convert or cast) to return a binary field as a string without actually converting it or casting it?
The data I want looks like this in the database:
0x24FC40460F58D64394A06684E9749F30
When using convert(varchar(max), binary_field), it comes back like this:
$ü#FXÖC” f„étŸ0
cast(binary_field as varchar(max)) had the same results.
I'm trying to modify a datasource in an old vb.net application, so I want it to be a string like the existing values, but still look like the original data. I don't have to do it in the query, but I'd like to if possible to avoid modifying the old vb code too much.
Here is my select statement:
SELECT strName, strDesc, binUUID
FROM MyTableName
where intFamily = '1234'
order by strName
Alternatively, if I do cast/convert it, would it be safe to compare "$ü#FXÖC” f„étŸ0" stored as a string at a later time to another value gathered in the same way?
There is a built in function to generate hex strings from binary values
SELECT sys.fn_varbintohexstr (0x24FC40460F58D64394A06684E9749F30)