From [MSDN][1]

&gt; The primary method of installing LocalDB is by using the
&gt; SqlLocalDB.msi program. LocalDB is an option when installing any SKU
&gt; of SQL Server 2012 Express. **Select LocalDB on the Feature Selection
&gt; page during installation of SQL Server Express**. There can be only one
&gt; installation of the LocalDB binary files for each major SQL Server
&gt; Database Engine version. Multiple Database Engine processes can be
&gt; started and will all use the same binaries. An instance of the SQL
&gt; Server Database Engine started as the LocalDB has the same limitations
&gt; as SQL Server Express

![enter image description here][2]

Or you can download standalone **SqlLocalDB.msi** from the list of available downloads on the `SQL Express` downloading [page][3]

![enter image description here][4]


To locate `localdb` instance on your PC simply try to connect to `(localdb)\Projects`

![enter image description here][5]


  [1]: http://msdn.microsoft.com/ru-ru/library/hh510202.aspx
  [2]: http://i.stack.imgur.com/TWZp0.png
  [3]: http://www.microsoft.com/en-us/download/details.aspx?id=29062
  [4]: http://i.stack.imgur.com/Hyq3q.png
  [5]: http://i.stack.imgur.com/fKZd7.png

If you downloaded **SqlLocalDB.msi** You can use silent install.

    msiexec /i SqlLocalDB.msi /qn IACCEPTSQLLOCALDBLICENSETERMS=YES
Remember about administrative rights for installation !


Note for people who got SQL 2016. You do in fact need to choose &quot;Express&quot; during installation of SQL 2016 to choose &quot;localDB&quot; option. If you choose anything else (like Developer edition for example), &quot;localDB&quot; will not appear as option under &quot;Shared features&quot;

**Developer Edition**&lt;BR&gt;
[![enter image description here][1]][1]


**SQL Express**&lt;BR&gt;
[![enter image description here][2]][2]


  [1]: http://i.stack.imgur.com/ENTAZ.png
  [2]: http://i.stack.imgur.com/TdMKE.png

Question is old but I think this is allways nice to know:

How to check if you have LocalDB installed, and if you do have it, which version it is:

 1. Open Command Prompt
 2. Enter &quot;SqlLocalDB info&quot;
    (without quotes)
 3. Hit &#39;Enter&#39; and your should see something like 
[this][1],

which means you have version &quot;MSSQLLocalDB&quot; installed.

There are a couple of versions:

- v11.0
- v12.0
- v13.0
and
- MSSQLLocalDB

  [1]: https://i.stack.imgur.com/Afs2y.png

I want to compare two dates for my Android application, but I got a really weird issue.

For example:

If I set the `back in the past` date to 127 days ago:

    this.dateEvent = System.currentTimeMillis() - (127 * 24 * 3600 * 1000)

And then compare it to the current date (Days between)

		Calendar sDate = getDatePart(new Date(this.dateEvent));
		Calendar eDate = getDatePart(new Date(System.currentTimeMillis()));
		
		int daysBetween = 0;
		while (sDate.before(eDate))
		{
			sDate.add(Calendar.DAY_OF_MONTH, 1);
			daysBetween ++;
		}
		
		while (sDate.after(eDate))
		{
			eDate.add(Calendar.DAY_OF_MONTH, 1);
			daysBetween ++;
		}
		
		return daysBetween;

It will return 22 which is not at all what was expected.

Did I make something wrong or is that an issue with the `Calendar` class ?

Android Days between two dates

How can I know that how much data is transferred over wire in terms of size in kilobytes, megabytes?

Take for example 

    {
      &#39;a&#39;: 1,
      &#39;b&#39;: 2
    }

How do I know what is the size of this payload is and **not** the length or items in the object  

**UPDATE**

    content-encoding:gzip
    content-type:application/json
    Transfer-Encoding:chunked
    vary:Accept-Encoding

Size of json object? (in KBs/MBs)

If I have to work with `localdb`, do we need to install it separately?

I have SQL Server 2008 R2 Management Studio installed, SQL Server 2012 installed, .net 4.0.2 update installed. But I don&#39;t see localdb in the PC yet.

How to install localdb separately?

<p>If I have to work with <code>localdb</code>, do we need to install it separately?</p>
<p>I have SQL Server 2008 R2 Management Studio installed, SQL Server 2012 installed, .net 4.0.2 update installed. But I don't see localdb in the PC yet.</p>


I am trying to query my postgresql db to return results where a date is in certain month and year. In other words I would like all the values for a month-year. 

The only way i&#39;ve been able to do it so far is like this:

    SELECT user_id 
    FROM user_logs 
    WHERE login_date BETWEEN &#39;2014-02-01&#39; AND &#39;2014-02-28&#39;

Problem with this is that I have to calculate the first date and last date before querying the table. Is there a simpler way to do this?

Thanks 

Postgresql query between date ranges

What does `||` do in SQL?

    SELECT &#39;a&#39; || &#39;,&#39; || &#39;b&#39; AS letter

What does SQL Select symbol || mean?

I have a postgresql function

    CREATE OR REPLACE FUNCTION fixMissingFiles() RETURNS VOID AS $$
	DECLARE
		deletedContactId integer;
        BEGIN
		        SELECT INTO deletedContactId contact_id FROM myContacts WHERE id=206351;
		
                -- print the value of deletedContactId variable to the console

        END;
    $$ LANGUAGE plpgsql;

How can I print the value of the deletedContactId to the console?

printing a value of a variable in postgresql

I need to remove some attributes from a json type column.

The Table:

    CREATE TABLE my_table( id VARCHAR(80), data json);
    INSERT INTO my_table (id, data) VALUES (
      &#39;A&#39;, 
      &#39;{&quot;attrA&quot;:1,&quot;attrB&quot;:true,&quot;attrC&quot;:[&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]}&#39;
    );

Now, I need to remove `attrB` from column `data`.

Something like `alter table my_table drop column data-&gt;&#39;attrB&#39;;` would be nice. But a way with a temporary table would be enough, too.

PostgreSQL: Remove attribute from JSON column

As I can understand [documentation][1] the following definitions are equivalent:

    create table foo (
        id serial primary key,
        code integer,
        label text,
        constraint foo_uq unique (code, label));

    create table foo (
        id serial primary key,
        code integer,
        label text);
    create unique index foo_idx on foo using btree (code, label);    

However, a note in [the manual for Postgres 9.4][2] says:

&gt; The preferred way to add a unique constraint to a table is `ALTER TABLE ... ADD CONSTRAINT`. The use of indexes to enforce unique constraints
&gt; could be considered an implementation detail that should not be
&gt; accessed directly.

(Edit: this note was removed from the manual with Postgres 9.5.)

Is it only a matter of good style? What are practical consequences of choice one of these variants (e.g. in performance)?


  [1]: https://www.postgresql.org/docs/current/indexes-unique.html
  [2]: https://www.postgresql.org/docs/9.4/indexes-unique.html

Postgres unique constraint vs index

I&#39;m getting this exception:

&gt; The parameterized query &#39;(@Name nvarchar(8),@type nvarchar(8),@units nvarchar(4000),@rang&#39; expects the parameter &#39;@units&#39;, which was not supplied.

My code for inserting is:

    public int insertType(string name, string type, string units = &quot;N\\A&quot;, string range = &quot;N\\A&quot;, string scale = &quot;N\\A&quot;, string description = &quot;N\\A&quot;, Guid guid = new Guid())
    {
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            SqlCommand command = new SqlCommand();
            command.CommandText = &quot;INSERT INTO Type(name, type, units, range, scale, description, guid) OUTPUT INSERTED.ID VALUES (@Name, @type, @units, @range, @scale, @description, @guid) &quot;;
            command.Connection = connection;
            command.Parameters.AddWithValue(&quot;@Name&quot;, name);
            command.Parameters.AddWithValue(&quot;@type&quot;, type);
            command.Parameters.AddWithValue(&quot;@units&quot;, units);
            command.Parameters.AddWithValue(&quot;@range&quot;, range);
            command.Parameters.AddWithValue(&quot;@scale&quot;, scale);
            command.Parameters.AddWithValue(&quot;@description&quot;, description);
            command.Parameters.AddWithValue(&quot;@guid&quot;, guid);
            return (int)command.ExecuteScalar();
        }
    }

The exception was a surprise because I&#39;m using the `AddWithValue` function and making sure I added a default parameters for the function. 


SOLVED:

The problem was that the some parameters where empty Strings (that override the default)

This is the working code: 

    public int insertType(string name, string type, string units = &quot;N\\A&quot;, string range = &quot;N\\A&quot;, string scale = &quot;N\\A&quot;, string description = &quot;N\\A&quot;, Guid guid = new Guid())
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                SqlCommand command = new SqlCommand();
                command.CommandText = &quot;INSERT INTO Type(name, type, units, range, scale, description, guid) OUTPUT INSERTED.ID VALUES (@Name, @type, @units, @range, @scale, @description, @guid) &quot;;
                command.Connection = connection;
                command.Parameters.AddWithValue(&quot;@Name&quot;, name);
                command.Parameters.AddWithValue(&quot;@type&quot;, type);

                if (String.IsNullOrEmpty(units))
                {
                    command.Parameters.AddWithValue(&quot;@units&quot;, DBNull.Value); 
                }
                else
                    command.Parameters.AddWithValue(&quot;@units&quot;, units);
                if (String.IsNullOrEmpty(range))
                {
                    command.Parameters.AddWithValue(&quot;@range&quot;, DBNull.Value);
                }
                else
                    command.Parameters.AddWithValue(&quot;@range&quot;, range);
                if (String.IsNullOrEmpty(scale))
                {
                    command.Parameters.AddWithValue(&quot;@scale&quot;, DBNull.Value);
                }
                else
                    command.Parameters.AddWithValue(&quot;@scale&quot;, scale);
                if (String.IsNullOrEmpty(description))
                {
                    command.Parameters.AddWithValue(&quot;@description&quot;, DBNull.Value);
                }
                else
                    command.Parameters.AddWithValue(&quot;@description&quot;, description);
                
                
                
                
                command.Parameters.AddWithValue(&quot;@guid&quot;, guid);


                return (int)command.ExecuteScalar();
            }
            
            
        }

The parameterized query ..... expects the parameter &#39;@units&#39;, which was not supplied

I&#39;m installing SQL Server 2012 at the moment and when I was about to run the installation, this error pops up: 

![The errors can be seen clearly in this picture][1]


On clicking the first failed test, which is &quot;Reporting Services Catalog Database File Existence&quot;, this is what i get:

![enter image description here][2]


On clicking the second failed test, which is &quot;Reporting Services Catalog Temporary Database File Existence&quot;, this is what i get:

![enter image description here][3]


  [1]: http://i.stack.imgur.com/rgr1C.png
  [2]: http://i.stack.imgur.com/Ipmqu.png
  [3]: http://i.stack.imgur.com/MV3XS.png

So basically, both of the message box says me that &quot;Catalog Database File&quot; &amp; &quot;Catalog Temporary database files exists&quot;. Because of this, i need to select Reporting Services file-only mode installation. 

My questions are:

 1. How do i select file-only mode installation?
 2. Do i&#39;ve to close the setup and do something and afterwards run the setup again?
 
Btw, I had SQL Server 2012 installed before. I uninstalled it completely due to some strange errors and decided to reinstall a fresh copy of SQL Server 2012 and now I&#39;m stuck with these errors. Any help will be sincerely appreciated. :)

SQL Server 2012 installation Reporting Services Catalog error

Ok so I have searched for an answer to this on Technet, to no avail.  

I just want to print an integer variable concatenated with two String variables. 

This is my code, that doesn&#39;t run:

    print &#39;There are &#39; + @Number + &#39; alias combinations did not match a record&#39;

It seems like such a basic feature, I couldn&#39;t imagine that it is not possible in T-SQL. But if it isn&#39;t possible, please just say so. I can&#39;t seem to find a straight answer.

Printing integer variable and string on same line in SQL

I have a server that is capable of creating and running an Excel Import task using the Import Wizard. I am trying to automate that process by using a visual Studio 2010 Integration Services package, that I am developing on that server.

The problem happens when trying to design the package.  I have added an excel connection and pointed it at the Excel file on a local disk (the same file I have already successfully imported using the import wizard). When I add an Excel Source to the DataFlow and specify the excel connection, when I go to the Name Of the Excel Sheet Drop down I just see &quot;No tables or views can be loaded&quot; and get the following error.

&quot;Could not retrieve the table information for the connection manager.
Failed to connect to the source using the connection manager ...&quot;

I can&#39;t find this error logged anywhere and i don&#39;t know why it is failing. The directory is shared to Authenticated users and the file is not in use.

Any ideas how to debug this error? I understand there can be issues running this in 64 bit mode, but does that apply to development?

I should add that it is an excel 2007 file .XLSX and the connection is set to Excel 2007.

2019-11-08 The answer by GavB841 below looks promising, if anyone tries it and it works please let me know. (I am no longer working in this area.)

SSIS Excel Connection Manager failed to Connect to the Source

sqlalchemy, a db connection module for Python, uses SQL Authentication (database-defined user accounts) by default. If you want to use your Windows (domain or local) credentials to authenticate to the SQL Server, the connection string must be changed.

By default, as defined by sqlalchemy, the connection string to connect to the SQL Server is as follows:

    sqlalchemy.create_engine(&#39;mssql://*username*:*password*@*server_name*/*database_name*&#39;)

This, if used using your Windows credentials, would throw an error similar to this:

    sqlalchemy.exc.DBAPIError: (Error) (&#39;28000&#39;, &quot;[28000] [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for us
    er &#39;***S\\username&#39;. (18456) (SQLDriverConnect); [28000] [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for us
    er &#39;***S\\username&#39;. (18456)&quot;) None None

In this error message, the code 18456 identifies the error message thrown by the SQL Server itself. This error signifies that the credentials are incorrect.

How do I connect to SQL Server via sqlalchemy using Windows Authentication?

I&#39;m using SQL Server 2014 Express and the LocalDB option, and I have the following in my SQL Server object explorer pane in Visual Studio 2013...

![enter image description here][1]

  [1]: http://i.stack.imgur.com/ZlDR7.png

So what is the difference between `(localdb)\ProjectsV12` &amp; `(localdb)\MSSQLLocalDB`?

LocalDB SQL Server 2014 Express creates 2 instances (localdb)\ProjectsV12 &amp; (localdb)\MSSQLLocalDB?

### Problem

I don&#39;t understand how to make LocalDB show up in the SQL Server Object Explorer. On some VMs, it shows up automatically, on some other VMs, it doesn&#39;t. Still, after googling for hours, I don&#39;t get it.

### Current situation

1. I have a clean VM
1. I installed Visual Studio 2015 Community (all default settings)
1. I let a console application run (Entity Framework 6, code-first, console application) which worked on another VM and created a database automatically which then showed up in the SQL Server Object Explorer; but not this time

The error says:

    System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 52 - Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database Runtime feature is enabled.) ---&gt; System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified

So, on this VM, no database gets created and nothing shows up in the SQL Server Object Explorer&#39;s `SQL Server` node.

[![Connecting to LocalDB][1]][1]


### What I think to know

- Visual Studio 2015 Community comes with LocalDB; so everything should just work out of the box, but it doesn&#39;t, and I don&#39;t know why
- LocalDB databases are just a pair of files (*.mdf and *.ldf)
- I&#39;ve seen the files being created at the default database location at `C:\Users\&lt;username&gt;\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\MSSQLLocalDB`; but on this VM, there is no such folder
- The `App.config` looked every time like this (and it was automatically created that way when I installed Entity Framework 6 the NuGet Package Manager in Visual Studio):

### App.config

    &lt;configuration&gt;
      &lt;configSections&gt;
        &lt;section name=&quot;entityFramework&quot; type=&quot;System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089&quot; requirePermission=&quot;false&quot; /&gt;
    &lt;/configSections&gt;
      &lt;entityFramework&gt;
        &lt;defaultConnectionFactory type=&quot;System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework&quot;&gt;
          &lt;parameters&gt;
            &lt;parameter value=&quot;mssqllocaldb&quot; /&gt;
          &lt;/parameters&gt;
        &lt;/defaultConnectionFactory&gt;
        &lt;providers&gt;
          &lt;provider invariantName=&quot;System.Data.SqlClient&quot; type=&quot;System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer&quot; /&gt;
        &lt;/providers&gt;
      &lt;/entityFramework&gt;
    &lt;/configuration&gt;

### Other random comments

- Earlier, with SQL Server, it was necessary to open up certain ports, but LocalDB runs, as I understand it, as a separate process on demand when started by Visual Studio.
- I don&#39;t know how to debug the `SQLException`
- Does LocalDB not come packaged with Visual Studio 2015 Community and do I need to install it separately?

  [1]: http://i.stack.imgur.com/NsZiq.png

How to add LocalDB to Visual Studio 2015 Community&#39;s SQL Server Object Explorer?

I am getting an error, While I am trying to connect (LocalDB)\MSSQLLocalDB through SQL Server management studio. I also tried to login with default database as master the error is same.

[![enter image description here][1]][1]
Here is the Server details.
[![enter image description here][2]][2]


  [1]: http://i.stack.imgur.com/Q3Gyb.png
  [2]: http://i.stack.imgur.com/dE9Aw.png

Content Type	Original Author	Original Content on Stackoverflow
Question	user1687824	View Question on Stackoverflow
Solution 1 - Sql	Andrey Morozov	View Answer on Stackoverflow
Solution 2 - Sql	mr R	View Answer on Stackoverflow
Solution 3 - Sql	Gregory Suvalian	View Answer on Stackoverflow
Solution 4 - Sql	Sed	View Answer on Stackoverflow

How to install localdb separately?

Sql Problem Overview

Sql Solutions

Solution 1 - Sql

Solution 2 - Sql

Solution 3 - Sql

Solution 4 - Sql

Size of json object? (in KBs/MBs)

Android Days between two dates

Attributions