Try this:    


    ORDER BY [reuestId] IS NULL DESC, [reuestId] DESC


should work (for mySql)


    SELECT *
    FROM TableX
    ORDER BY (requestId IS NOT NULL)
           , requestId DESC

How do I use the new line character in R? 

    myStringVariable &lt;- &quot;Very Nice ! I like&quot;;
    
    myStringVariabel &lt;- paste(myStringVariable, &quot;\n&quot;, sep=&quot;&quot;);

The above code **DOESN&#39;T work**

P.S There&#39;s significant challenges when googling this kind of stuff since the query &quot;R new line character&quot; does seem to confuse google. I really wish R had a different name. 

R - do I need to add explicit new line character with print()?

We host a multitenant app with SQLAlchemy and postgres. I am looking at moving from having separate databases for each tenant to a single database with multiple schemas. Does SQLAlchemy support this natively? I basically just want every query that comes out to be prefixed with a predetermined schema... e.g

    select * from client1.users

instead of just 

    select * from users

Note that I want to switch the schema for all tables in a particular request/set of requests, not just a single table here and there.

I imagine that this could be accomplished with a custom query class as well but I can&#39;t imagine that something hasn&#39;t been done in this vein already.

SQLAlchemy support of Postgres Schemas

mysql order by, null first, and DESC after

I want a value to be set to `NULL` if nothing is put into the text box in the form I&#39;m submitting. How can I make this happen?
I&#39;ve tried inserting `&#39;NULL&#39;` but this just adds the word `NULL` into the field.

I&#39;m not sure what code I should provide for this, I&#39;m just writing an UPDATE query.

Set value to NULL in MySQL

I&#39;m trying to grab the date from my database in a standard timestamp and display it as ISO 8601.  I&#39;m unable to easily do it in PHP so I&#39;m trying to do it in my SELECT statement.  This is what I have, but it displays an error:

    SELECT * FROM table_name ORDER BY id DESC DATE_FORMAT(date,&quot;%Y-%m-%dT%TZ&quot;)
What am I doing wrong?

Format date in MySQL SELECT as ISO 8601

I am trying to use a `dict` to do a SQL `INSERT`. The logic would basically be:

    INSERT INTO table (dict.keys()) VALUES dict.values()

However, I am having a tough time figuring out the correct syntax / flow to do this. This is what I currently have:

    # data = {...}
    sorted_column_headers_list = []
    sorted_column_values_list = []
    for k, v in data.items():
        sorted_column_headers_list.append(k)
        sorted_column_values_list.append(v)
    sorted_column_headers_string = &#39;, &#39;.join(sorted_column_headers_list)
    sorted_column_values_string = &#39;, &#39;.join(sorted_column_values_list)
            
    cursor.execute(&quot;&quot;&quot;INSERT INTO title (%s) 
                VALUES (%s)&quot;&quot;&quot;, 
                (sorted_column_headers_string, sorted_column_values_string))

From this I get a SQL exception (I think related to the fact that commas are also included in some of the values that I have). What would be the correct way to do the above?

Using a Python dict for a SQL INSERT statement

I&#39;m trying to find out if my table will get less performant if I change the primary key to BIGINT(20). At the moment, I&#39;m using INT(7) and have about **300.000 entries already with large IDs (7 or 8 digits)**.
I searched a lot already but only found out that it uses more disk-space (which is obvious). 

All of my IDs have 7 digits right now, but my customer wants to change to 8 digits. I won&#39;t be able to easily change the software in the future, so I thought about using BIGINT(20) now just in case. Would it be less performant if I use BIGINT even though I don&#39;t need to yet?

Does anyone with experience doing this have suggestions regarding speed and performance?

BIGINT mysql performance compared to INT

In MySQL how do I define a custom sorting order. 

To try to explain what I want consider this table:

    ID	Language	Text
    0	ENU			a
    0	JPN			b
    0	DAN			c		
    1	ENU			d
    1	JPN			e
    1	DAN			f
    2	etc...

here I want to return all rows sorted by Language and ascending ID so that Language = ENU comes first, then JPN and lastly DAN. 

The result should be: a,d,b,e,c,f etc.

Is this even possible?

How to define a custom ORDER BY order in mySQL

I need to sort a PostgreSQL table ascending by a date/time field, e.g. `last_updated`.

But that field is allowed to be empty or null and I want records with null in `last_updated` come *before* non-null `last_updated`.  
Is this possible?

    order by last_updated asc  -- and null last_updated records first ??

Sort by column ASC, but NULL values first?

If I have a table and data like this:

    ID |  Name  |  Group   

    1    Apple     A    

    2    Boy       A

    3    Cat       B

    4    Dog       C

    5    Elep      C

    6    Fish      C

and I wish to order it according to the total of Group from smallest to largest value, such as :
A - 2 records , B - 1 record , C - 3 records , so it will become:


    3    Cat       B

    1    Apple     A    

    2    Boy       A

    4    Dog       C

    5    Elep      C

    6    Fish      C
  


I tried    

        $sql = &quot;SELECT ID,Name FROM table ORDER BY COUNT(Group)&quot;;

but it just returns one result for me.

Are there any hints? Thank you.
    

SQL Order By Count

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

As I know, from the relational database theory, a `select` statement without an `order by` clause should be considered to have no particular order. But actually in SQL Server and Oracle (I&#39;ve tested on those 2 platforms), if I query from a table without an `order by` clause multiple times, I always get the results in the same order. Does this behavior can be relied on? Anyone can help to explain a little?


The order of a SQL Select statement without Order By clause

The following SQL is from Itzik Ben-Gan that is used to generate a numbers table. What does the `order by (select null)` part mean? Thanks.

    DECLARE @number_of_numbers INT;
    SELECT @number_of_numbers = 100000;
    
    WITH    a AS ( SELECT   1 AS i
                   UNION ALL
                   SELECT   1
                 ),
            b AS ( SELECT   1 AS i
                   FROM     a AS x ,
                            a AS y
                 ),
            c AS ( SELECT   1 AS i
                   FROM     b AS x ,
                            b AS y
                 ),
            d AS ( SELECT   1 AS i
                   FROM     c AS x ,
                            c AS y
                 ),
            e AS ( SELECT   1 AS i
                   FROM     d AS x ,
                            d AS y
                 ),
            f AS ( SELECT   1 AS i
                   FROM     e AS x ,
                            e AS y
                 ),
            numbers
              AS ( SELECT TOP ( @number_of_numbers )
                            ROW_NUMBER() OVER ( ORDER BY ( SELECT   NULL
                                                         ) ) AS number
                   FROM     f
                 )
        SELECT  *
        FROM    numbers;

Thanks!

Content Type	Original Author	Original Content on Stackoverflow
Question	Ervin	View Question on Stackoverflow
Solution 1 - Mysql	DonCallisto	View Answer on Stackoverflow
Solution 2 - Mysql	ypercubeᵀᴹ	View Answer on Stackoverflow

mysql order by, null first, and DESC after

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

SQLAlchemy support of Postgres Schemas

R - do I need to add explicit new line character with print()?

Attributions