You are thinking in the function `ABS`, that gives you the absolute value of numeric data.

    SELECT ABS(a) AS AbsoluteA, ABS(b) AS AbsoluteB
    FROM YourTable




**The best solution is:** from positive to negative or from negative to positive

For negative:

    SELECT ABS(a) * -1 AS AbsoluteA, ABS(b) * -1 AS AbsoluteB
    FROM YourTable

For positive:

    SELECT ABS(a) AS AbsoluteA, ABS(b)  AS AbsoluteB
    FROM YourTable



    UPDATE mytbl
    SET a = ABS(a)
    where a &lt; 0

Use the absolute value function [ABS][1].  The syntax is 

    ABS ( numeric_expression )


  [1]: http://msdn.microsoft.com/en-us/library/ms189800.aspx

An easy and straightforward solution using the **CASE** function:

    SELECT CASE WHEN ( a &gt; 0 ) THEN (a*-1) ELSE (a*-1) END AS NegativeA,
           CASE WHEN ( b &gt; 0 ) THEN (b*-1) ELSE (b*-1) END AS PositiveB
    FROM YourTableName


I&#39;m trying to make a _very_ simple &#39;counter&#39; that is supposed to keep track of how many times my program has been executed.

First, I have a textfile that only includes one character: `0`

Then I open the file, parse it as an `int`, add `1` to the value, and then try to return it to the textfile:

    f = open(&#39;testfile.txt&#39;, &#39;r+&#39;)
    x = f.read()
    y = int(x) + 1
    print(y)
    f.write(y)
    f.close()

I&#39;d like to have `y` overwrite the value in the textfile, and then close it.  &lt;br&gt;&lt;/br&gt;&lt;br&gt;
But all I get is `TypeError: expected a character buffer object`.

### Edit:  

Trying to parse `y` as a string:


    f.write(str(y))

gives

    IOError: [Errno 0] Error



TypeError: expected a character buffer object - while trying to save integer to textfile

Started to use the add-migration command in the package manager console to generate the migrations for my model. My question is, the up and down method. I assume that the purpose of the down method is to remove all dependencies and drop the tables if they are already in the database? Also that the down method will be executed before the up method?
The up method is then the reverse, create/update tables/indexes etc?

Sometimes when i use this then the down method gets a lot of create tables that then are dropped? Recently it created and dropped a lot of tables and almost the same thing happened in the up method. Why?

C# Code-First migration, up/down?

The current data of the table is:

      a   b
    ---------
     -1   5
    -11   2
     -5  32

My request is to convert every data into a positive value.

Unfortunately, I forgot the name of the built-in function of SQL Server that enables to convert.



Convert negative data into positive data in SQL Server

The current data of the table is:
<pre><code class="hljs language-markdown"> a b
---------
 -1 5
-11 2
 -5 32
</code></pre>
My request is to convert every data into a positive value.
Unfortunately, I forgot the name of the built-in function of SQL Server that enables to convert.

I believe the title is self-explanatory. How do you create the table structure in  PostgreSQL to make a many-to-many relationship.

My example:

    Product(name, price);
    Bill(name, date, Products);

How to implement a many-to-many relationship in PostgreSQL?

I want to run this query:

    SELECT DISTINCT ON (address_id) purchases.address_id, purchases.*
    FROM purchases
    WHERE purchases.product_id = 1
    ORDER BY purchases.purchased_at DESC

But I get this error:

&gt; PG::Error: ERROR:  SELECT DISTINCT ON expressions must match initial ORDER BY expressions

Adding `address_id` as first `ORDER BY` expression silences the error, but I really don&#39;t want to add sorting over `address_id`. Is it possible to do without ordering by `address_id`?

PostgreSQL DISTINCT ON with different ORDER BY

I&#39;ve been trying to update a specific row for a while now, and it seems that there are two ways to do this. From what I&#39;ve read and tried, you can just use the:

`execSQL(String sql)` method 

or the:

`update(String table, ContentValues values, String whereClause, String[] whereArgs)` method.

(Let me know if this is incorrect as I am new to android and very new to SQL.)

So let me get to my actual code.

    myDB.update(TableName, &quot;(Field1, Field2, Field3)&quot; + &quot; VALUES (&#39;Bob&#39;, 19, &#39;Male&#39;)&quot;, &quot;where _id = 1&quot;, null);

I am trying to accomplish this:

Update Field1, Field2, and Field3 where the primary key (_id) is equal to 1.

Eclipse gives me a red line right underneath the word &quot;update&quot; and gives me this explanation:

&gt; The method update(String, ContentValues, String, String[]) in the type
&gt; SQLiteDatabase is not applicable for the arguments (String, String,
&gt; String, null)

I&#39;m guessing I&#39;m not assigning the ContentValues correctly. Can anyone point me in the right direction?

SQLite in Android How to update a specific row

Can someone please tell me how to show all privileges/rules from a specific user in the sql-console?


How to show all privileges from a user in oracle?

I tried the following select:

    SELECT (id,name) FROM v_groups vg 
    inner join people2v_groups p2vg on vg.id = p2vg.v_group_id
    where p2vg.people_id =0;

and I get the following error column reference `id` is ambiguous.

Thing is if I try the same `SELECT` but I only ask for `name`, and not for `id` also, it works.
I&#39;m new to this and maybe I am missing something obvious. Any suggestions? 

Thanks.

Postgresql column reference &quot;id&quot; is ambiguous

Is there MS SQL Server function that counts the number of times a particular character appears in a string?   

Number of times a particular character appears in a string

After installing SQL Server 2008, I cannot find the `SQL Server Configuration Manager` in `Start / SQL Server 2008 / Configuration Tools` menu. 

What should I do to install this tool?

SQL Server Configuration Manager not found

As demonstrated by previous Stack Overflow questions ([https://stackoverflow.com/questions/2425550/transactionscope-and-connection-pooling][1] and [https://stackoverflow.com/questions/3759897/how-does-sqlconnection-manage-isolationlevel][2]), the transaction isolation level leaks across pooled connections with SQL Server and ADO.NET (also System.Transactions and EF, because they build on top of ADO.NET).

This means, that the following dangerous sequence of events can happen in any application:

 1. A request happens which requires an explicit transaction to ensure data consistency
 2. Any other request comes in which does not use an explicit transaction because it is only doing uncritical reads. This request will now execute as serializable, **potentially causing dangerous blocking and deadlocks**

The question: **What is the best way to prevent this scenario?** Is it really required to use explicit transactions everywhere now?

Here is a self-contained repro. You will see that the third query will have inherited the Serializable level from the second query.

    class Program
    {
        static void Main(string[] args)
        {
            RunTest(null);
            RunTest(IsolationLevel.Serializable);
            RunTest(null);
            Console.ReadKey();
        }

        static void RunTest(IsolationLevel? isolationLevel)
        {
            using (var tran = isolationLevel == null ? null : new TransactionScope(0, new TransactionOptions() { IsolationLevel = isolationLevel.Value }))
            using (var conn = new SqlConnection(&quot;Data Source=(local); Integrated Security=true; Initial Catalog=master;&quot;))
            {
                conn.Open();

                var cmd = new SqlCommand(@&quot;
    select         
            case transaction_isolation_level 
                WHEN 0 THEN &#39;Unspecified&#39; 
                WHEN 1 THEN &#39;ReadUncommitted&#39; 
                WHEN 2 THEN &#39;ReadCommitted&#39; 
                WHEN 3 THEN &#39;RepeatableRead&#39; 
                WHEN 4 THEN &#39;Serializable&#39; 
                WHEN 5 THEN &#39;Snapshot&#39; 
            end as lvl, @@SPID
         from sys.dm_exec_sessions 
        where session_id = @@SPID&quot;, conn);

                using (var reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        Console.WriteLine(&quot;Isolation Level = &quot; + reader.GetValue(0) + &quot;, SPID = &quot; + reader.GetValue(1));
                    }
                }

                if (tran != null) tran.Complete();
            }
        }
    }

Output:

    Isolation Level = ReadCommitted, SPID = 51
    Isolation Level = Serializable, SPID = 51
    Isolation Level = Serializable, SPID = 51 //leaked!


  [1]: https://stackoverflow.com/questions/2425550/transactionscope-and-connection-pooling
  [2]: https://stackoverflow.com/questions/3759897/how-does-sqlconnection-manage-isolationlevel

SQL Server: Isolation level leaks across pooled connections

I created a table `tbl_Candidate`, but I forgot to set the primary key to the table and I saved it without primary key.

Next time I&#39;m going to set primary key in SQL Server 2008 Express, I get a message like I have to drop the table and recreate when I&#39;m going to save the table with primary key changes.

This is the message that pops up when I&#39;m trying to save changes in the table:

&gt; Saving changes is not permitted. The changes you have made require
&gt; that the following tables to dropped and recreate. You have either made
&gt; changes to the table that can&#39;t be recreate or enable the option
&gt; prevent saving changes that require the tables to be recreate

I&#39;m logged into SQL Server with Windows authentication, server type as database engine and Server name as `.\SQLExpress`.

Please give me a way to correct this problem or way to change the settings of the SQL Server.

Can&#39;t change table design in SQL Server 2008

I need to select a field called ProgramID from a table and if the ProgramID is NULL then I need to select the value in the InterimProgramID from the same table and alias it as ProgramID.

How can I make a conditional SELECT statement to do this?

Content Type	Original Author	Original Content on Stackoverflow
Question	What'sUP	View Question on Stackoverflow
Solution 1 - Sql	Lamak	View Answer on Stackoverflow
Solution 2 - Sql	Abdul Saboor	View Answer on Stackoverflow
Solution 3 - Sql	Sam DeHaan	View Answer on Stackoverflow
Solution 4 - Sql	Adam Porad	View Answer on Stackoverflow
Solution 5 - Sql	ruddy simonpour	View Answer on Stackoverflow

Convert negative data into positive data in SQL Server

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C# Code-First migration, up/down?

TypeError: expected a character buffer object - while trying to save integer to textfile

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