I've got a field in my DB that's an arbitrary value on a per-row basis, and I'd like to add X to this. I'd only like to add X if a flag word (held as an int in this row) has the 2nd and 10th bits set true. Is it possible to create an SQL statement to do this for every row in the table? Or do I have to iterate through my entire table?
Using MySQL (5.5)
Bonus points question: I say add X based on a flag, but there's also a scaling factor. For example, based on a value of bits 20-12 interpreted as a short unsigned integer, I'd really like to assign:
value = value + ('X' * thatShort * (bit2 and bit10));
In MS SQL:
update MyTable
set Field1 = Field1 + 'X'
where Field2 & 0x202 = 0x202
[EDIT]
value = value (X * (field & 0x1FF800 >> 12) * 0x202)
0x1FF800 - is the mask from 12 to 20.
>> 11 - shift it to remove bits from 0 to 12.
since you are filtering by bit2 and bit10 set, then (bit2 and bit10) = 0x202
Hope this will answer your question. Not sure how you are going to grant 'bonus points' though :).
Related
I need to anonymize a variable in SQL data (VAR NAME = "ArId").
The variable contains 10 numbers + 1 letter + 2 numbers. I need to randomize the 10 first numbers and then keep the letter + the last two numbers.
I have tried the rand() function, but this randomize the whole value.
SELECT TOP 1000 *
FROM [XXXXXXXXXXX].[XXXXXXXXXX].[XXXXX.TEST]
I have only loaded the data.
EDIT (from "answer"):
I have tried: UPDATE someTable
SET someColumn = CONCAT(CAST(RAND() * 10000000000 as BIGINT), RIGHT(someColumn, 3))
However as i am totally new to SQL i don't know how to make this work. I put 'someColumn = new column name for the variable i am crating. RIGHT(someColumn) = the column i am changing. When i do that i get the message that the right function requires 2 arguments??
Example for Zohar: I have a variable containing for example: 1724981628R01On all these values in this variable i would like to randomize the first 10 letters and keep the last three (R01). How can i do that?
A couple things. First, your conversion to a big int does not guarantee that the results has the right number of characters.
Second, rand() is constant for all rows of the query. Try this version:
UPDATE someTable
SET someColumn = CONCAT(FORMAT(RAND(CHECKSUM(NEWID())
), '0000000000'
),
RIGHT(someColumn, 3)
);
Using SQL in PostgreSQL I need to select all the rows from my table called "crop" when the first digit of the integer numbers in column "field_id" is 7.
select *
from crop
where (left (field_id,1) = 7)
First, you know that the column is a number, so I would be inclined to explicitly convert it, no matter what you do:
where left(crop::text, 1) = '7'
where crop::text like '7%'
The conversion to text is simply to be explicit about what is happening and it makes it easier for Postgres to parse the query.
More importantly, if the value has a fixed number of digits, then I would suggest using a numeric range; something like this:
where crop >= 700000 and crop < 800000
This makes it easier for Postgres to use an index on the column.
Try with cast, like this:
select *
from crop
where cast(substring(cast(field_id as varchar(5)),1,1) as int) = 7
where 5 in varchar(5) you should put number how long is your integer.
I keep number representation of binary data in BigQuery table
I need to be able to search by BitPos and find out if bit on given position in 0 or 1
Oracle analog is BitTest
Use this function to return TRUE (1) if the specified bit in a value is a 1; otherwise return FALSE (0).
Syntax BitTest(Value1, BitPos)
Example: number in DB is 1099511627780
So it is binary 10000000000000000000000000000000000000100
Thus Results are:
BitTest(1099511627780, 1) = 0;
BitTest(1099511627780, 2) = 0;
BitTest(1099511627780, 3) = 1;
Can you help me to find native implementation in BigQuery?
I was looking through doc with no luck
https://cloud.google.com/bigquery/docs/reference/standard-sql/functions-and-operators
You can create a temporary function that performs this computation using a bit shift and bitwise and. Here is an example:
CREATE TEMP FUNCTION BitTest(value INT64, bit INT64) AS (
value >> (bit - 1) & 0x1 = 1
);
SELECT
value,
bit,
BitTest(value, bit) AS result
FROM (
SELECT 1099511627780 AS value, bit
FROM UNNEST(GENERATE_ARRAY(1, 42)) AS bit
)
ORDER BY bit;
The function BitTest checks whether the bit at the 1-based index is set. The FROM clause in this example generates bit indexes between 1 and 42 to demonstrate what the output is.
I am trying to update multiple rows with random 9 digit number using the following code.
UPDATE SGT_EMPLOYER
SET SSN = (CONVERT(NUMERIC(10,0),RAND() * 899999999) + 100000000)
WHERE EMPLOYER_ACCOUNT_ID = 123456789;
Expected result: the query should update 300 rows with 300 random 9 digit numbers.
Actual: query is updating 300 rows with same number as the ran() function is executing only once.
Please help. Thank You.
As you already figured out yourself, RAND is a run-time constant function in SQL Server. It means that it is called once per statement and the generated value is used for each affected row.
There are other functions that are called for each row. Often people use NEWID usually together with CHECKSUM as a substitute for a random number, but I would not recommend it because the distribution of such random numbers is likely to be poor.
There is a good function specifically designed to generate random numbers: CRYPT_GEN_RANDOM. It is available since at least SQL Server 2008.
It generates a given number of random bytes.
In your case it would be convenient to have a random number as a float value in the range of [0;1], same as the value returned by RAND.
So, CRYPT_GEN_RANDOM(4) generates 4 random bytes as varbinary.
Convert them to int, divide by the maximum value of 32-bit integer (4294967295) and add 0.5 to shift the range from [-0.5;+0.5] to [0;1]:
(CAST(CRYPT_GEN_RANDOM(4) as int) / 4294967295.0 + 0.5)
Your query becomes:
UPDATE SGT_EMPLOYER
SET SSN =
CONVERT(NUMERIC(10,0),
(CAST(CRYPT_GEN_RANDOM(4) as int) / 4294967295.0 + 0.5) * 899999999.0 + 100000000.0)
WHERE EMPLOYER_ACCOUNT_ID = 123456789;
Yes, the rand() line will only be executed once, before the rows are being updated, not every time a row is updated.
You can use a Stored Procedure to update every row with (CONVERT(NUMERIC(10,0),RAND() * 899999999) + 100000000).
Sean Lange is 100% correct. However, if you want to quickly mask your SSN, perhaps the following using HashBytes() may help.
Example
Declare #Table table (SSN varchar(25))
Insert into #Table values
('070-99-12345'),
('123-45-67890')
Select SSN
,AsInt = abs(cast(HashBytes('MD5', SSN) as int))
From #Table
Returns
SSN AsInt
070-99-12345 508860145
123-45-67890 843256257
This is the scenario. I have a column 'flag' in a table. This column stores a 32bit binary number in decimal form. For example 00000000000000000000000000000010 is stored as 2. I need to display all the records in the table in which the 26th bit of the value stored in 'flag' is set as '1'. How do I write sql query for this purpose?
Try this:
select * from tablename
where (flag & 64) = 64
The 26th bit corresponds to bit for 2 ^ 6 = 64. On SQL Server, & will do a bitwise-AND and return 64 only if the 64 bit is set in both operands.