SQL Server Configuration Manager in Windows 10

September 16, 2018

I needed to set an instance setting for a SQL Server instance, so I went to open SQL Server Configuration Manager (I’m running Windows 10 and SQL Server 2017 Developer edition). I’m used to seeing this as a stand-alone option, but I didn’t see it listed with my available programs.
It turns out that this functionality is now found in MMC(Microsoft Management Console). It can be accessed from the Control Panel, under Administrative Tools, then Computer Management.
I would have never found this on my own, luckily I found this article:
SuperUser.com


Convert String To DateTime For A Specific Time Zone

August 31, 2018

I recently had a project where we were receiving a file with a date stamp in the file name, in the format yyyyMMddHHmm, so the date plus the hour and minute. The file was produced on the West Coast in Pacific time (I’m in the Eastern time zone). We want to store that date/time, where we store time as UTC.
Because of daylight saving time (DST), we can’t just add a set number of hours to the Pacific time to get UTC, unless we can determine if the input time in in standard time or DST. I’ve worked at places where we maintained a table with all of the start and end dates for DST, and would look up each time in order to convert the time.
Luckily, SQL Server has support for standard time and DST to determine which is appropriate for a specific time.
Here is the SQL code I ended up using.

DECLARE @input char(12) = '201808311200';
DECLARE @output datetimeoffset;

DECLARE @year int = CAST(SUBSTRING(@input, 1, 4) AS int);
DECLARE @month tinyint = CAST(SUBSTRING(@input, 5, 2) AS tinyint);
DECLARE @day tinyint = CAST(SUBSTRING(@input, 7, 2) AS tinyint);
DECLARE @hour tinyint = CAST(SUBSTRING(@input, 9, 2) AS tinyint);
DECLARE @minute tinyint = CAST(SUBSTRING(@input, 11, 2) AS tinyint);

SET @output = (DATETIMEFROMPARTS(@year, @month, @day, @hour, @minute, 0, 0)) AT TIME ZONE 'Pacific Standard Time';

SET @output = @output AT TIME ZONE 'UTC';

SELECT @output;

First, I parsed the input string into the separate date/time parts. Alternatively, We could have added formatting to the input string (Like 2018-08-31 12:00:00) and converted that directly to a datetime.
If we use the datetimeoffset data type, we can use the AT TIME ZONE statement to designate what time zone our time is in. In this case (with Pacific time), we’ll end up with an offset of -7:00. We’ll use ‘Pacific Standard Time’ even though DST is in effect, since the point of the functionality is for us to not have to make the DST determination.
You can query the sys.time_zone_info system table to see a list of the time zones that can be used with this statement.
We’ll make one last conversion to UTC to end up with the datetime that we’ll store.

While on the subject of time zones, here are a few things on UTC. UTC stands for Coordinated Universal Time, the acronym is a compromise between the English and French phrases. (Wikipedia).
People use UTC and GMT(Greenwich Mean Time) as synonyms, and the time for each in within fractions of a second, but there is a difference between the two. GMT is a time zone, and is based on astronomical observations. UTC is a time standard (not a time zone) as in based on atomic clocks.


Docker And SQL Server

July 29, 2018

Containers:
Containers are a way to virtualize a single application, as opposed to virtualizing an entire server. We can run an application in this container without installing the product or worrying about all of the dependencies of that application. Everything needed to run an application is in the container.

Docker:
Docker is the most popular platform for running and managing containers.

Prerequsites for Installing Docker:
To install Docker on Windows, we’ll need to have Microsoft Windows 10 Professional or Enterprise 64-bit(You can also run on Windows Server), we need a version that will support virtualization. We also need virtualization enabled on the machine (You’ll need to go into the BIOS to enable this).
We’ll need Hyper-V and Containers features enabled as well. We can do this in the Control Panel, or use Cortanta to search for ‘Turn Windows features on and off’. Make sure the Containers and the Hyper-V items are checked. The Docker installation will check to see if these features are enabled, and will give you the option to enable these features then, but setting these before hand will save you a reboot.
Notes that if Hyper-V is enabled, then Virtual Box will not work, if you have that installed.

Installing Docker:
The Docker Community Edition for Windows is a free download, but you’ll need to set up a Docker login.
The install is pretty straight forward. For my example, I checked to Use Windows containers instead of Linux containers.

Basic Docker Commands:
We can use the Command Prompt or the Powershell Window to run Docker command, I used Powershell for these examples.

docker --version

: This will return the version and build number for the Docker install.

docker --help

: This will give us a list of available Docker commands. We can also use this to get additional information on a specific command, for example if we wanted more information on the version command, we would run docker version –help.

Sample Docker Container:
We can run a sample Hello World container just to make sure everything is set up on running correctly. We can run the command:

docker run hello-world

This will pull down the Hello World image and run it. If everything is running correctly, you’ll see a message ‘Hello From Docker!’. If things aren’t set up correctly you’ll see an error message.
Initially I got an error:
“container xxx encountered an error during CreateContainer: failure in a Windows system call: No hypervisor is present on this system.”
I had let the Docker install enable the Containers and Hyper-V components for me. When I went to check on the options, The Hyper-V Platform option under Hyper-V was greyed out with the message “Hyper-v cannot be installed: Virtualization support is disabled in the firmware”. It turned out that Virtualization was turned off on my laptop, which prevented this option from being enabled. I didn’t get an error during the install when it trying to enable these features, and it took me a while to figure out the issues. So I would recommend running through the prereqs yourself, instead of relying on the install to do this.

Other Docker Commands:

docker images

: List all of the installed images.

docker rmi hello-world -f

: To remove an image (hello-world). The -f flag will force removal.

docker container ls

: List running containers

Running SQL Server:
Now to a more practical use. We can run SQL Server in Docker. A container for SQL Server Developer edition is available through Docker Hub . We can view some information on the container here.
We can run this command to download the container:

docker pull microsoft/mssql-server-windows-developer

The download is 4-5 gigs.
Once we have pulled the container down, we can start it up:

docker run -d -p 1433:1433 -e sa_password=WeakPW12 -e ACCEPT_EULA=Y microsoft/mssql-server-windows-developer

It will take a few seconds to start up. Once the container is running, we’ll see an ID printed to the console. Make a note of this ID.
So there are a few parameters that have been set in the run command. -d means detached, which means that the container runs in the background. -p (for publish) designates the port for the service, we’ll stick with the SQL Server default of port 1433. We list two ports, one for the container and another for the host. -e will set an environment variable, in this case we’ll indicate that we accept the user agreement. We’re also using -e to set the sa password for this session. At first, I set a very simple sa password, and then I had issues trying to connect to SQL Server. When creating the sa password, you’ll have to follow the complexity requirements for a sa password, you won’t get an error message for an invalid password. The sa password has a 8 character minimum, plus you’ll need at least 3 from upper case letters, lower case letters, numbers and special characters.
We can connect to our SQL Server container either with the SQLCMD command line tool, or with SSMS. For this example, we’ll use SSMS.
To connect with SSMS, we’ll need to get the IP address for our running SQL Server. Using the ID we got when starting the container, we’ll run this command:

docker inspect {ID}

You can also use the 12 character Container ID. We can get that ID by running:

docker ps

In the output, we’ll go to Network Settings / Network / IP Address , and make a note of this address.
To connect with SSMS, we’ll use the IP Address as the Server Name (include a comma then the port number if not using the default port). Select SQL Server Authentication, then use sa and the sa password we passed in when starting the container.
Once we’ve connected, we can use SSMS to create objects, or open a query window, just as we would with any SQL Server.

Once we’ve completed, we can stop the container passing in the Container ID for {ID}:

docker stop {ID}

Once we stop the container, we’ll lose whatever objects and data that we’ve set up. It is possible to map the container to use data and log files on the host machine, this page goes through the setup for that.

Links:
Get started with Docker
Windows Containers
Docker Documentation
SQL Server 2016 Express Edition in Windows containers


Incorrect syntax was encountered while parsing GO

June 30, 2018

I have a Powershell script I created to script out the views and stored procedures in a database. Usually I just use it to find all the references to a particular table or column, but in this case I wanted to run the procedure on another database. When running the script, I ran into this error:
“A fatal scripting error occurred.
Incorrect syntax was encountered while parsing GO.”

The error came from the SQL in this script. (The issue is dependent on formatting, I couldn’t get the format to come through in the WordPress page).

At first I was puzzled, everything looked fine to me. I did have the extra space in the front of the third line, so I deleted it and re-ran. Still with the same error. I knew that GO needed to be on its own line (unless I added a number to indicate I wanted the batch to run that many times).
I came across this post that described the same error. I didn’t have anything on the same line as the GO, but I decided to check my Powershell script. Instead if using a carriage return and line feed after the GO:
`r`n

I had inadvertently used a `v (a vertical tab) instead of a `n. Error on my part, but easily corrected.
Instead of regenerating my script, I could also save a copy of the script from SSMS.
In the Save dialog, select the arrow next to the Save button and select Save With Encoding.
Under Line Endings, change ‘Current Setting’ to ‘Windows (CR LF)’, then click OK and then Save.


Running Totals

May 28, 2018

Displaying a running total in SQL Server is very straightforward, thanks to window functions and the OVER clause.
We’ll set up an example with some records for a payment amount over several days.

drop table if exists #Test;

create table #Test (
PaymentDate date not null primary key,
Amount int not null
);

insert into #Test(PaymentDate, Amount) 
values ('2018-05-29', 25), ('2018-05-30',10), ('2018-05-31',20), 
	('2018-06-01',30), ('2018-06-02',40), ('2018-06-03', 15);

select * from #Test;

Adding a running total is just a matter of SUM with an OVER clause.

select PaymentDate, Amount,
	sum(Amount) over (order by PaymentDate) as RunningTotal
from #Test
order by PaymentDate;

The RunningTotal column will show the total of all payments made on that day and any earlier date.

We can also use PARTITION to display a running total for just that month as well.

select PaymentDate, Amount, datename(month, PaymentDate) as MonthName,
	sum(Amount) over (partition by month(PaymentDate) order by PaymentDate) as MonthRunningTotal
from #Test
order by PaymentDate;

In the first example we used default settings for the OVER clause, which is for the current row plus all rows before it. Here is the first query with the default explicitly given.

select PaymentDate, Amount,
	sum(Amount) over (order by PaymentDate rows unbounded preceding) as RunningTotal
from #Test
order by PaymentDate;

We can change this setting to return other combinations. In the final example, we’ll return the running total as the payment amount for the current row plus the amount from the day before.


select PaymentDate, Amount,
	sum(Amount) over (order by PaymentDate rows 1 preceding) as RunningTotal
from #Test
order by PaymentDate;

Window Functions
SELECT – OVER Clause


T-SQL – SET vs SELECT

April 22, 2018

When assigning values to a variable, we can use SET or SELECT. SET is the ANSI standard method. If we have a set value we want to assign to a variable, either method works just as well as the other. When we are retrieving values from a table or view, then there are some differences in behavior.
In order to run through some examples, we’ll set up a temp table with 1 column and 2 rows of data.

drop table if exists #Test;
create table #Test (RecordId int not null primary key);
insert into #Test(RecordId) values (1), (2);

When selecting by the primary key, we know we’ll get one value, so things are straightforward.

declare @VarSelect int;
declare @VarSet int;

select @VarSelect = RecordId from #Test where RecordId = 1;
set @VarSet = (select RecordId from #Test where RecordId = 1);

select @VarSelect as VarSelect, @VarSet as VarSet;

Let’s try an example of retrieving a value that doesn’t exist in the table. We’ll set 0 as the default value for the variables.

declare @VarSelect int = 0;
declare @VarSet int = 0;

select @VarSelect = RecordId from #Test where RecordId = 3;
set @VarSet = (select RecordId from #Test where RecordId = 3);

select @VarSelect as VarSelect, @VarSet as VarSet;

Using the SET method will return NULL, where the SELECT will leave the default value in place. If we’re using the variable one time, this behavior may not cause issues, but reusing the variable could cause confusion.
In the following example, the first select will return 1. The second select won’t find a value, so it will also return 1.

declare @VarSelect int = 0;

select @VarSelect = RecordId from #Test where RecordId = 1;
select @VarSelect as VarSelect;

select @VarSelect = RecordId from #Test where RecordId = 3;
select @VarSelect as VarSelect;

When returning multiple values, a SET will raise this error:
“Msg 512, Level 16, State 1, Line x
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, , >= or when the subquery is used as an expression.”
The SELECT will return one of the values from the result set.

declare @VarSelect2 int = 0;
declare @VarSet2 int = 0;

select @VarSelect2 = RecordId from #Test;
set @VarSet2 = (select RecordId from #Test);

select @VarSelect2 as VarSelect, @VarSet2 as VarSet;

In this case, I would rather an error be thrown that to just return one of the result set values.
Overall, it seems like SET it the better choice. We’ll get an error if multiple values are returned, and if no value is returned then we’ll get a NULL.


Converting Float Values To Strings

March 26, 2018

A coworker and I were looking at a request where we needed to write float values to a file, but have the values be of a uniform length (In this case, the float column was storing a monetary value, which isn’t a good idea, but that’s what we had to work with). In this case, all values were out to 4 decimal places, so it was a matter of padding the value to the left of the decimal to get everything to an equal length. The first thought was to convert the value to a string, pad the from with zeros, and from that take a string of the specified length.
To my surprise, it turns out that casting a float to a string data type (a varchar in this case) ends up rounding the value in some cases, and converting to scientific notation in others. With a little Googling we found out that using the STR function is the recommended way to make this conversion. STR takes has length and decimal value parameters to control how many digits are output.
I had used the FORMAT function for dates before, but it also handles numbers as well. This turned out to be the approach that was used, since in the FORMAT function we can specify padding to a certain length.
Here’s SQL for some test data long with the different approaches.

create table dbo.FloatTest(
FloatValue float not null
);

insert into dbo.FloatTest values (123.45678);
insert into dbo.FloatTest values (2.66993256);
insert into dbo.FloatTest values (0.00001);
insert into dbo.FloatTest values (55555.84);
insert into dbo.FloatTest values (321.0987654);

select  FloatValue as OriginalValue, 
        cast(FloatValue as varchar(15)) as CastValue,
	str(FloatValue, 20, 10) as StrValue, 
	format(FloatValue, 'F9') as FormatValue,
	format(FloatValue, '0000000000.##########') as CustomFormatValue
from dbo.FloatTest;

go

With FORMAT, we can specify a standard format for floats with F, followed by the number of decimal digits. Or we can create a custom format. Using a 0 for a required digit and a # for an optional digit allows us greater control over what is returned.