I need to mask data in my tables, for example data like:
ABCDEFG
XYZABCD
LMNOPQR
Should appear like:
AB*****
XY*****
LM*****
What update query can I use? Also, can I use a single query for updating multiple columns?
You can just mask it when showing the data
select stuff(stuff(stuff(col,3,3,'*'),7,3,'*'),10,3,'*')) as col from table
Suppose the column you want to mask is called column from table table, than you can use the following query, which is standard in SQL, to update the value in the column:
update table
set column = substring(column from 1 for 2) || '****';
If on the other hand you want only to select the values to show them, you can use the following query:
select substring(column from 1 for 2) || '****'
from table;
Related
To find for one column, I can use this.
SELECT column1
FROM `dataset.table`
WHERE column1 IS NULL OR column1 = '';
But what if i have 100 columns? Instead of going through column by column, changing column 1 to 2,3,etc.,I'm looking for one for all solution. I'm kinda new to SQL and Data Cleaning.
Consider below approach
select *
from your_table t
where regexp_contains(to_json_string(t), r':(?:null|"")[,}]')
above will return you all rows where any column either null or empty string
Column1 EventTypes_pKey
Are 5,3
Test 1,4,5
test 1,3,5
If I am using
Select * from Table name where EventTypes_pKey in('5,1,4)
then I want that record where these value belongs the column.
How I can use where condition on the basis of EventTypes_pKey this is my Varchar column.
I want If I am selecting 5,3,4 the there should be all three row data.
Please help me.
If you are using Postgres, you can do this by by converting the value into an array and then using the overlaps operator &&
select *
from badly_designed_table
where string_to_array(eventtypes_pkey, ',')::int[] && array[5,3,4];
Online example
Does SQLite offer a way to search every column of a table for a searchkey?
SELECT * FROM table WHERE id LIKE ...
Selects all rows where ... was found in the column id. But instead to only search in the column id, I want to search in every column if the searchstring was found. I believe this does not work:
SELECT * FROM table WHERE * LIKE ...
Is that possible? Or what would be the next easy way?
I use Python 3 to query the SQLite database. Should I go the route to search through the dictionary after the query was executed and data returned?
A simple trick you can do is:
SELECT *
FROM table
WHERE ((col1+col2+col3+col4) LIKE '%something%')
This will select the record if any of these 4 columns contain the word "something".
No; you would have to list or concatenate every column in the query, or reorganize your database so that you have fewer columns.
SQLite has full-text search tables where you can search all columns at once, but such tables do not work efficiently with any other queries.
I could not comment on #raging-bull answer. So I had to write a new one. My problem was, that I have columns with null values and got no results because the "search string" was null.
Using coalesce I could solve that problem. Here sqlite chooses the column content, or if it is null an empty string (""). So there is an actual search string available.
SELECT *
FROM table
WHERE (coalesce(col1,"") || coalesce(col2,"") || coalesce(col3,"") || coalesce(col4,"")) LIKE '%something%')
I'm not quite sure, if I understood your question.
If you want the whole row returned, when id=searchkey, then:
select * from table where id=searchkey;
If you want to have specific columns from the row with the correct searchkey:
select col1, col2, col3 from table where id=searchkey;
If you want to search multiple columns for the "id": First narrow down which columns this could be found in - you don't want to search the whole table! Then:
select * from table where col1=searchkey or col2=searchkey or col3=searchkey;
So I'm trying to get a part of a value from a column and insert that part into another column - new column. BOTH columns are in the same table. So what i want should look something like this:
id newColumn oldColumn
1 12 123 some text
2 24 246 some text
....
I know how to get 12 and 24 using SUBSTR, but how do i enter the data for each row in the table. Should i be using self-join or something else?
First you have to add new col using following command:-
ALTER TABLE TAB_NAME
ADD COLUMN COL_NAME(VARCHAR(10));
After that execute this command:-
UPDAET TAB_NAME
SET COL_NAME = SUBSTRING(OLDCOLUMN, 1, 2);
I think this might help you.
No need to join, it's just a plain UPDATE:
update tablename set newColumn = substring(oldColumn from 1 for 2)
substring is ANSI SQL, some dbms have substr and other versions.
The question is why you are doing this? What do you expect to find in newColumn if someone later updates oldColumn to another value? Maybe you should have a view instead, where newColumn always has up to date values?
Please get into the habit of ALWAYS specifying the DB engine you are using... It helps us to help you - we can provide more relevant answers.
You might want to consider using a calculated column as opposed to storing the information again.
In SQL Server you could do something like this
ALTER TABLE YourTable
ADD new_column as SUBSTRING(old_column, 1, 2);
This way you don't need to insert or update this column it is always consistent with the original column. and you just use it in your select statement in the usual way.
select new_column from YourTable
I understand that AS is used to create an alias. Therefore, it makes sense to have one long name aliased as a shorter one. However, I am seeing a SQL query NULL as ColumnName
What does this imply?
SELECT *, NULL as aColumn
Aliasing can be used in a number of ways, not just to shorten a long column name.
In this case, your example means you're returning a column that always contains NULL, and it's alias/column name is aColumn.
Aliasing can also be used when you're using computed values, such as Column1 + Column2 AS Column3.
When unioning or joining datasets using a 'Null AS [ColumnA] is a quick way to make sure create a complete dataset that can then be updated later and a new column does not need to be created in any of the source tables.
In the statement result we have a column that has all NULL values. We can refer to that column using alias.
In your case the query selects all records from table, and each result record has additional column containing only NULL values. If we want to refer to this result set and to additional column in other place in the future, we should use alias.
It means that "aColumn" has only Null values. This column could be updated with actual values later but it's an empty one when selected.
---I'm not sure if you know about SSIS, but this mechanism is useful with SSIS to add variable value to the "empty" column.
When using SELECT you can pass a value to the column directly.
So something like :
SELECT ID, Name, 'None' AS Hobbies, 0 AS NumberOfPets, NULL AS Picture, '' AS Adress
Is valid.
It can be used to format nicely a query output when using UNION/UNION ALL.
Query result can have a new column that has all NULL values. In SQL Server we can do it like this
SELECT *, CAST(NULL AS <data-type>) AS as aColumn
e.g.
SELECT *, CAST(NULL AS BIGINT) AS as aColumn
How about without using the the as
SELECT ID
, Name
, 'None' AS Hobbies
, 0 AS NumberOfPets
, NULL Picture
Usually adding NULL as [Column] name at the end of a select all is used when inserting into another table a calculated column based on the table you have just selected.
UPDATE #TempTable SET aColumn = Column1 + Column2 WHERE ...
Then exporting or saving the results to another table.