Re: hiding column values for specific rows

Luca Ferrari wrote:
> Hi,
> I don't know if this's possible but I'd like to hide column values for 
> specific rows within a query. Imagine I've got a table with columns username 
> and password: users(username,password). Now I'd like the user registered in 
> the table to see her password, to see who is registered but not to see the 
> other people passwords. For example, if the table contains:
> username  | password
> --------------+-------------
> luca            | myPaswd
> roberto       | otherPaswd
> gianna        | thirdPaswd
> 
> I'd like to do a query like: "SELECT * FROM users where username=luca" 
> obtaining something like:
> username  | password
> --------------+-------------
> luca            | myPaswd
> roberto       | xxxxx
> gianna        | XXXXX
> 
> Is it possible to specify in the above query that all password columns that do 
> not belong to selected row (username=luca) must be hidden? Anyone has an idea 
> about how to implement this on the database side?
> 
> Thanks,
> Luca
> 
You could try:
select username,case when username='luca' then password else 'XXXXXX' 
end as password from users;

Note that the the username 'luca' corresponds to the user querying the 
table.