[LEAST][1](a, b):
&gt; The `GREATEST` and `LEAST` functions select the largest or smallest value from a list of any number of expressions. The expressions must all be convertible to a common data type, which will be the type of the result (see [Section 10.5](https://www.postgresql.org/docs/current/static/typeconv-union-case.html) for details). NULL values in the list are ignored. The result will be NULL only if all the expressions evaluate to NULL.
&gt; 
Note that `GREATEST` and `LEAST` are not in the SQL standard, but are a common extension. Some other databases make them return NULL if any argument is NULL, rather than only when all are NULL...


  [1]: https://www.postgresql.org/docs/current/functions-conditional.html#FUNCTIONS-GREATEST-LEAST

Here&#39;s the link to docs for the `LEAST()` function in PostgreSQL:

http://www.postgresql.org/docs/current/static/functions-conditional.html#AEN15582

You can get the answer by putting that data into a column like this:

    SELECT name, MIN(score_a, score_b) as minimum_score
    FROM table

Here, we are putting the minimum value among `score_a` and `score_b` and printing the same by storing that value in a column named `minimum_score`.

Why does everyone tell me writing code like this is a bad practice?

    if (foo)
        Bar();

    //or

    for(int i = 0 i &lt; count; i++)
        Bar(i);

My biggest argument for omitting the curly braces is that it can sometimes be twice as many lines with them. For example, here is some code to paint a glow effect for a label in C#.

    using (Brush br = new SolidBrush(Color.FromArgb(15, GlowColor)))
    {
        for (int x = 0; x &lt;= GlowAmount; x++)
        {
            for (int y = 0; y &lt;= GlowAmount; y++)
            {
                g.DrawString(Text, this.Font, br, new Point(IconOffset + x, y));
            }
         }
     }
     //versus
    using (Brush br = new SolidBrush(Color.FromArgb(15, GlowColor)))
        for (int x = 0; x &lt;= GlowAmount; x++)
            for (int y = 0; y &lt;= GlowAmount; y++)
                g.DrawString(Text, this.Font, br, new Point(IconOffset + x, y));

You can also get the added benefit of chaining `usings` together without having to indent a million times.

    using (Graphics g = Graphics.FromImage(bmp))
    {
        using (Brush brush = new SolidBrush(backgroundColor))
        {
            using (Pen pen = new Pen(Color.FromArgb(penColor)))
            {
                //do lots of work
            }
        }
     }
    //versus
    using (Graphics g = Graphics.FromImage(bmp))
    using (Brush brush = new SolidBrush(backgroundColor))
    using (Pen pen = new Pen(Color.FromArgb(penColor)))
    {
        //do lots of work
    }


----------


The most common argument for curly braces revolves around maintance programming, and the problems that would ensue by inserting code between the original if statement and its intended result:

    if (foo)
        Bar();
        Biz();


----------
&lt;h3&gt;Questions:&lt;/h3&gt;

 1. Is it wrong to want to use the more compact syntax which the language offers? The people that design these languages are smart, I can&#39;t imagine they would put a feature which is always bad to use.
 2. Should we or Shouldn&#39;t we write code so the lowest common denominator can understand and have no problems working with it? 
 3.  Is there another argument that I&#39;m missing?

Why is it considered a bad practice to omit curly braces?

I have to change some connection strings in an incredibly old legacy application, and the programmers who made it thought it would be a great idea to plaster the entire app with connection strings all over the place.

Visual Studio&#39;s &quot;current project&quot; search is incredible slow, and I don&#39;t trust Windows Search.

So, what&#39;s the best free, non-indexed text search tool out there? All it should do is return a list with files that contain the wanted string inside a folder and its subfolders. 

I&#39;m running Windows 2003 Server.



Tools to search for strings inside files without indexing

Let&#39;s say I have a table like this:

    name | score_a | score_b
    -----+---------+--------
     Joe |   100   |   24
     Sam |    96   |  438
     Bob |    76   |  101
     ... |   ...   |  ...

I&#39;d like to select the minimum of score_a and score_b. In other words, something like:

    SELECT name, MIN(score_a, score_b)
    FROM table

The results, of course, would be:

    name | min
    -----+-----
     Joe |  24
     Sam |  96
     Bob |  76
     ... | ...

However, when I try this in Postgres, I get, &quot;No function matches the given name and argument types. You may need to add explicit type casts.&quot; MAX() and MIN() appear to work across *rows* rather than *columns.*

Is it possible to do what I&#39;m attempting?

How do I get the MIN() of two fields in Postgres?

Let's say I have a table like this:
<pre><code class="hljs language-diff">name | score_a | score_b
-----+---------+--------
 Joe | 100 | 24
 Sam | 96 | 438
 Bob | 76 | 101
 ... | ... | ...
</code></pre>
I'd like to select the minimum of score_a and score_b. In other words, something like:
<pre><code class="hljs language-sql">SELECT name, MIN(score_a, score_b)
FROM table
</code></pre>
The results, of course, would be:
<pre><code class="hljs language-lua">name | min
-----+-----
 Joe | 24
 Sam | 96
 Bob | 76
 ... | ...
</code></pre>
However, when I try this in Postgres, I get, "No function matches the given name and argument types. You may need to add explicit type casts." MAX() and MIN() appear to work across rows rather than columns.
Is it possible to do what I'm attempting?

I have a SQL Server database and I want to know what columns and types it has. I&#39;d prefer to do this through a query rather than using a GUI like Enterprise Manager. Is there a way to do this?

What is the equivalent of &#39;describe table&#39; in SQL Server?

I&#39;ve seen a number of people claim that you should specifically name each column you want in your select query.

Assuming I&#39;m going to use all of the columns anyway, why would I not use `SELECT *`?

Even considering the question *[SQL query - Select * from view or Select col1, col2, … colN from view][1]*, I don&#39;t think this is an exact duplicate as I&#39;m approaching the issue from a slightly different perspective.  

One of our principles is to not optimize before it&#39;s time.  With that in mind, it seems like using `SELECT *` should be the **preferred** method until it is proven to be a resource issue or the schema is pretty much set in stone.  Which, as we know, won&#39;t occur until development is completely done.

That said, is there an overriding issue to not use `SELECT *`?

  [1]: https://stackoverflow.com/questions/128412/sql-query-question-select-from-view-or-select-col1col2from-view


What is the reason not to use select *?

I have a trigger in which I want to have a variable that holds an INT I get from a `SELECT`, so I can use it in two IF statements instead of calling the `SELECT` twice. How do you declare/use variables in MySQL triggers?

MySQL Trigger - Storing a SELECT in a variable

I&#39;m trying to use MySQL to create a view with the &quot;WITH&quot; clause

    WITH authorRating(aname, rating) AS
       SELECT aname, AVG(quantity)
       FROM book
       GROUP BY aname

But it doesn&#39;t seem like MySQL supports this.

I thought this was pretty standard and I&#39;m sure Oracle supports this. Is there anyway to force MySQL to use the &quot;WITH&quot; clause?  I&#39;ve tried it with the MyISAM and innoDB engine.  Both of these don&#39;t work.


MySQL &quot;WITH&quot; clause

    SELECT NR_DZIALU, COUNT (NR_DZIALU) AS LICZ_PRAC_DZIALU
        FROM  PRACOWNICY
        GROUP BY NR_DZIALU
        HAVING NR_DZIALU = 30

or

    SELECT NR_DZIALU, COUNT (NR_DZIALU) AS LICZ_PRAC_DZIALU
        FROM PRACOWNICY
        WHERE NR_DZIALU = 30
        GROUP BY NR_DZIALU

Which SQL statement is faster? (HAVING vs. WHERE...)

I&#39;m running a project on a Postgres database and need to retrieve the comments on columns within the DB to be used as table headings and such. I have seen that there are a couple of built in functions ([pg_description](http://www.postgresql.org/docs/9.1/static/catalog-pg-description.html) and [col_description](http://www.postgresql.org/docs/9.1/static/functions-info.html)) but i haven&#39;t been able to find examples on how to use them and playing around with them has proved pretty futile.

So I was wondering if any has been able to do this before and if so, how?

Retrieving Comments from a PostgreSQL DB

In output of explain command I found two terms &#39;Seq Scan&#39; and &#39;Bitmap heap Scan&#39;. Can somebody tell me what is the difference between these two types of scan? (I am using PostgreSql)

What is the difference between Seq Scan and Bitmap heap scan in postgres?

SQLAlchemy&#39;s `DateTime` type allows for a `timezone=True` argument to save a non-naive datetime object to the database, and to return it as such. Is there any way to modify the timezone of the `tzinfo` that SQLAlchemy passes in so it could be, for instance, UTC? I realize that I could just use `default=datetime.datetime.utcnow`; however, this is a naive time that would happily accept someone passing in a naive localtime-based datetime, even if I used `timezone=True` with it, because it makes local or UTC time non-naive without having a base timezone to normalize it with. I have tried (using [pytz][1]) to make the datetime object non-naive, but when I save this to the DB it comes back as naive.

Note how datetime.datetime.utcnow does not work with `timezone=True` so well:

    import sqlalchemy as sa
    from sqlalchemy.sql import select
    import datetime

    metadata = sa.MetaData(&#39;postgres://user:pass@machine/db&#39;)

    data_table = sa.Table(&#39;data&#39;, metadata,
        sa.Column(&#39;id&#39;,   sa.types.Integer, primary_key=True),
        sa.Column(&#39;date&#39;, sa.types.DateTime(timezone=True), default=datetime.datetime.utcnow)
    )

    metadata.create_all()

    engine = metadata.bind
    conn = engine.connect()
    result = conn.execute(data_table.insert().values(id=1))

    s = select([data_table])
    result = conn.execute(s)
    row = result.fetchone()
&gt; (1, datetime.datetime(2009, 1, 6, 0, 9, 36, 891887))

    row[1].utcoffset()
&gt; datetime.timedelta(-1, 64800) # that&#39;s my localtime offset!!

    datetime.datetime.now(tz=pytz.timezone(&quot;US/Central&quot;))
&gt; datetime.timedelta(-1, 64800)

    datetime.datetime.now(tz=pytz.timezone(&quot;UTC&quot;))
&gt; datetime.timedelta(0) #UTC

Even if I change it to explicitly use UTC:

...
    
    data_table = sa.Table(&#39;data&#39;, metadata,
        sa.Column(&#39;id&#39;,   sa.types.Integer, primary_key=True),
        sa.Column(&#39;date&#39;, sa.types.DateTime(timezone=True), default=datetime.datetime.now(tz=pytz.timezone(&#39;UTC&#39;)))
    )

    row[1].utcoffset()
...
&gt; datetime.timedelta(-1, 64800) # it did not use the timezone I explicitly added

Or if I drop the `timezone=True`:

...

    data_table = sa.Table(&#39;data&#39;, metadata,
        sa.Column(&#39;id&#39;,   sa.types.Integer, primary_key=True),
        sa.Column(&#39;date&#39;, sa.types.DateTime(), default=datetime.datetime.now(tz=pytz.timezone(&#39;UTC&#39;)))
    )
    
    row[1].utcoffset() is None
...
&gt; True # it didn&#39;t even save a timezone to the db this time

  [1]: http://pytz.sourceforge.net/

SQLAlchemy DateTime timezone

In Postgresql, how can I do a condition to create a table only if it does not already exist? 

Code example appreciated. 

Postgresql: how to create table only if it does not already exist?

How can you get the active users connected to a postgreSQL database via SQL? This could be the userid&#39;s or number of users.

How can you get the active users connected to a postgreSQL database via SQL?

Given the following table in SQL Server 2005:

    ID   Col1   Col2   Col3
    --   ----   ----   ----
    1       3     34     76  
    2      32    976     24
    3       7    235      3
    4     245      1    792

What is the best way to write the query that yields the following result (i.e. one that yields the final column - a column containing the minium values out of Col1, Col2, and Col 3 **for each row**)?

    ID   Col1   Col2   Col3  TheMin
    --   ----   ----   ----  ------
    1       3     34     76       3
    2      32    976     24      24
    3       7    235      3       3
    4     245      1    792       1


***UPDATE:***

For clarification (as I have said in the coments) in the real scenario the database is **properly normalized**. These &quot;array&quot; columns are not in an actual table but are in a result set that is required in a report. And the new requirement is that the report also needs this MinValue column. I can&#39;t change the underlying result set and therefore I was looking to T-SQL for a handy &quot;get out of jail card&quot;.

I tried the CASE approach mentioned below and it works, although it is a bit cumbersome. It is also more complicated than stated in the answers because you need to cater for the fact that there are two min values in the same row.

Anyway, I thought I&#39;d post my current solution which, given my constraints, works pretty well. It uses the UNPIVOT operator:

    with cte (ID, Col1, Col2, Col3)
    as
    (
    	select ID, Col1, Col2, Col3
    	from TestTable
    )
    select cte.ID, Col1, Col2, Col3, TheMin from cte
    join
    (
    	select
    		ID, min(Amount) as TheMin
    	from 
    		cte 
    		UNPIVOT (Amount for AmountCol in (Col1, Col2, Col3)) as unpvt
    	group by ID
    ) as minValues
    on cte.ID = minValues.ID

I&#39;ll say upfront that I don&#39;t expect this to offer the best performance, but given the circumstances (I can&#39;t redesign all the queries just for the new MinValue column requirement), it is a pretty elegant &quot;get out of jail card&quot;.




What&#39;s the best way to select the minimum value from several columns?

From C++, are `std::min` and `std::max` preferable over `fmin` and `fmax`?  For comparing two integers, do they provide basically the same functionality? 

Do you tend to use one of these sets of functions or do you prefer to write your own (perhaps to improve efficiency, portability, flexibility, etc.)?

***Notes:***

 1. The C++ Standard Template Library (STL) declares the `min` and `max` functions in the standard C++ [algorithm][1] header.  

 2. The C standard (C99) provides the `fmin` and `fmax` function in the standard C [math.h][2] header.

Thanks in advance!

  [1]: http://en.wikipedia.org/wiki/Algorithm_(C%2B%2B)
  [2]: http://en.wikipedia.org/wiki/Math.h

Use of min and max functions in C++

I&#39;m producing a list of decimal values from a LINQ expression and I want the minimum non zero value. However it&#39;s entirely possible that the LINQ expression will result in an empty list.

This will raise an exception and there is no MinOrDefault to cope with this situation.

    decimal result = (from Item itm in itemList
                      where itm.Amount &gt; 0
                      select itm.Amount).Min();


How can I set the result to 0 if the list is empty?

How to achieve &quot;MinOrDefault&quot; in LINQ?

I&#39;m using Python&#39;s `max` and `min` functions on lists for a minimax algorithm, and I need the index of the value returned by `max()` or `min()`. In other words, I need to know which move produced the max (at a first player&#39;s turn) or min (second player) value.

    for i in range(9):
        new_board = current_board.new_board_with_move([i / 3, i % 3], player)
    
        if new_board:
            temp = min_max(new_board, depth + 1, not is_min_level)  
            values.append(temp)

    if is_min_level:
        return min(values)
    else:
        return max(values)

I need to be able to return the actual index of the min or max value, not just the value.

Getting the index of the returned max or min item using max()/min() on a list

If I have a Python dictionary, how do I get the key to the entry which contains the minimum value?

I was thinking about something to do with the `min()` function...

Given the input:

    {320:1, 321:0, 322:3}

It would return `321`.


Content Type	Original Author	Original Content on Stackoverflow
Question	mike	View Question on Stackoverflow
Solution 1 - Sql	cagcowboy	View Answer on Stackoverflow
Solution 2 - Sql	Bill Karwin	View Answer on Stackoverflow
Solution 3 - Sql	Mohamed Aamir	View Answer on Stackoverflow

How do I get the MIN() of two fields in Postgres?

Sql Problem Overview

Sql Solutions

Solution 1 - Sql

Solution 2 - Sql

Solution 3 - Sql

Tools to search for strings inside files without indexing

Why is it considered a bad practice to omit curly braces?

Attributions