How to remove line feeds (lf) and character return (cr) from a text field in SQL Server?

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I was doing some data cleaning the other day, I ran into the issue of text fields having line feeds (lf) and character returns (cr) — this creates a lot of issues when you do data import/export. I had run into this problem sometime before as well and didn’t remember what I did back then so I am putting the solution here so it can be referenced later if need be.

To solve this, you need to remove LF, CR and/or combination of both. here’s the T-SQL syntax for SQL Server to do so:

SELECT REPLACE(REPLACE(@YourFieldName, CHAR(10), ' '), CHAR(13), ' ')

if you’re using some other database system then you need to figure out how to identify CR and LF’s — in SQL Server, the Char() function helps do that and there should be something similar for the database system that you’re using.

What is the difference between Row_Number(), Rank() and Dense_Rank() in SQL?

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If the database that you work with supports Window/Analytic functions then the chances are that you have run into SQL use-cases where you have wondered about the difference between Row_Number(), Rank() and Dense_Rank(). In this post, I’ll show you the difference:

So, let’s just run all of them together and see what the output looks like.

Here’s my query: (Thanks StackExchange!)

select DisplayName,Reputation,
Row_Number() OVER (Order by Reputation desc) as RowNumber,
Rank() OVER (Order by Reputation desc) as Rank,
Dense_Rank() OVER (Order by Reputation desc) as DenseRank
from users

Which gives the following output:

DisplayName          Reputation RowNumber Rank DenseRank 

-------------------- ---------- --------- ---- --------- 

Hardik Mishra        9999       1         1    1         

Alex                 9997       2         2    2         

Omnipresent          9997       3         2    2         

Sergei Basharov      9993       4         4    3         

Oleg Pavliv          9991       5         5    4         

Jason Creighton      9991       6         5    4         

Aniko                9991       7         5    4         

Notlikethat          9990       8         8    5         

ZeMoon               9989       9         9    6         

Carl                 9987       10        10   7   
...
...
...     

Note that all the functions are essentially are “ranking” your rows but there are subtle differences:

  1. Row_Number() doesn’t care if the two values are same and it just ranks them differently. Note row #2 and #3, they both have value 9997 but they were assigned 2 and 3 respectively.
  2. Rank() — Now unlike Row_Number(), Rank() would consider that the two values are same and “Rank” them with same value. Note Row #2 and #3, they both have value 9997 and so both were assigned Rank “2” — BUT notice the Rank “3” is missing! In other words, it introduces some “gaps”
  3. Dense_Rank() — Now Dense_Rank() is like Rank() but it doesn’t leave any gaps! Notice that the Rank “3” in the DenseRank field.

I hope this clarified the differences between these SQL Ranking functions — let me know your thoughts in the comments section

Paras Doshi

How do I prepare myself to be a data analyst?

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Originally published on Quora: How do I prepare myself to be a Data Analyst?

Based on how you are framing your question, it seems that you currently don’t have “Data Analysis” Background but want to build a career in this field. Here are three things you could do:

  1. Learn Tech Skills: You will need technical knowledge to be successful at analyzing data. SQL and Excel are a good starting point. You could do a lot with these tools — then depending on the bandwidth that you might have you could explore R. How do you learn this? Here’s a learning pathway: Learn #Data Analysis online – free curriculum ; Also search for free courses on Coursera or other platforms.
  2. Learn Soft/Business Skills: This is as important as tech skills (if not more!) when it comes to Data Analysis. Finding Insights from your data is half the battle, you will need to put the insights in a context/story and influence business decisions and sometimes influence business change. we know change is always hard! So your soft/business skills will be very important. Also, you will benefit a lot from learning about how to break down problems, communicate your solution by using “business” language vs tech-speak.
  3. Apply them (and keep improving): Now that you have picked up some tech and soft/biz skills, apply them! Get an internship, Help out a non-profit in your free time (Data Kind, Statistics Without borders, Volunteer Match are good resources to find a non-profit) and start applying your skills! It would also help you get some “Real” world experience and applying what you have learned while “learning-on-the-job” is arguably the BEST way to pick something up!

Hope that helps!

[VIDEO] Microsoft’s vision for “Advanced analytics” (presented at #sqlpass summit 2015)

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Presented at #sqlpass summit 2015.

SQL Server Reporting services: How to display “There are NO rows” message?

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Problem:

You have a SQL Server reporting services (SSRS) report that has a table which displays some records — but sometimes it can have NO rows; In that case, how to display “There are No rows” message so that it doesn’t confuse the consumer.

Solution:

  1. Open the report in SQL Server Data Tools and go to the “design” tab of your SSRS report
  2. Select your table (do NOT select a cell inside a table. Make sure that the table is selected) SQL Server reporting services NO data rows message
  3. While the “table” is selected, Go the Properties section OR you can use F4
  4. Inside the Properties section, find “No Rows” section and you should see a NoRowsMessage property:SQL Server reporting services NO data rows message v2
  5. Go to the preview tab to make sure it’s working and you should be ready to deploy the change!

That’s it! Hope that helps.

Official reference:  https://msdn.microsoft.com/en-us/library/dd220407.aspx

Author: Paras Doshi

How to change the Data Source of a SQL Server Reporting Services Report (Native Mode)?

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Problem:

You have your SQL Server Reporting Services environment in native mode — and you want to modify the data source of a report there.

Solution:

  1. Navigate to Report Manager.
  2. Navigate to the Report that you want to Manage and run it
  3. After the report renders, you will have a breadcrumb navigation on the top right
  4. Click on the Last Part of the Breadcrumb NavigationSSRS properties report native mode
  5. It should open up the “properties” section of this report
  6. On the properties section, you should be able to manage the data source
    SSRS Manage Data Source Native Mode Shared
  7. Make the changes that you wanted to the data source settings of this SSRS report — and don’t forget to click “apply”
  8. Done!

Author: Paras Doshi

Back to Basics — What is DDL, DML, DCL & TCL?

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I was talking with a database administrator about different categories that SQL Commands fall into — and I thought it would be great to document here. So here you go:

ACRONYM DESCRIPTION SQL COMMANDS
DML Data Manipulation Language: SQL Statements that affect records in a table. SELECT, INSERT, UPDATE, DELETE
DDL Data Definition Language: SQL Statements that create/alter a table structure CREATE, ALTER, DROP
DCL Data Control Language: SQL Statements that control the level of access that users have on database objects GRANT, REVOKE
TCL Transaction Control Language: SQL Statements that help you maintain the integrity of data by allowing control over transactions COMMIT, ROLLBACK

BONUS (Advance) QUESTION:

Is Truncate SQL command a DDL or DML? Please use comment section!

Author: Paras Doshi