EDIT 19 Aug 2022: This post has not been updated for a long time, and the link to the sample code is broken. So, I recommend you take a look at Mala’s more recent blog post and associated script at https://www.sqlservercentral.com/articles/formatting-t-sql-scripts-using-scriptdom-and-powershell If you really want to look at my original sample code, a member of the community updated my older script and shared it as a gist: https://gist.github.com/jheidt/5320803
This is a ‘quick-and-not-so-dirty’ version of a T-SQL formatter / ‘pretty printer’ in PowerShell. To use this, please install the SQL 2012 SP1 version of the SQLDOM from the Feature Pack page. (If you already have SQL 2012 client tools on your machine, you should be ready to go.) And you will need PowerShell of course 
Here is a sample usage of this script:
tsqlpp.ps1 -Source c:temptestcases.sql -Target c:tempout.sql
Some usage tips:
- Right click and save the file to your machine, do NOT run it directly from this blog site
- To execute the script your PowerShell execution policy must be set to RemoteSigned
- The parser is by default set to 110 compatibility i.e. SQL 2012 syntax. If you are working with older compatibility levels feel free to edit the script to reference the 80, 90, 100 versions of the parser.
- The generated / formatted script will NOT contain comments, you will lose any comments you had in the unformatted version
Please leave your comments, suggestions and asks for future versions of the script in the Comments section of this post. Thank you and I’m glad to be of help to you!
Disclaimer: This script is provided AS IS with no warranties, and confer no rights.
Arvind Shyamsundar's technical blog 
Hi. do you have an updated URL for the tsqlpp.ps1 file as the link above seems to be old and no longer available?
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Hello Martin – I recommend you take a look at Mala’s more recent blog post and associated script at https://www.sqlservercentral.com/articles/formatting-t-sql-scripts-using-scriptdom-and-powershell
Also, a member of the community updated my older script and shared it as a gist: https://gist.github.com/jheidt/5320803
Hope this helps.
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How do you figure out the DOM structure? For example when I use ANTLR it is easy if I see the grammar file. In ScriptDOM there is not enough documentation to understand what in DOM stands for what in the syntax
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How do you figure out the DOM structure? For example when I use ANTLR I look at the grammar file and figure out. How can I figure out which class represents what in the DOM?
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ScriptDom is now open-source: https://github.com/microsoft/SqlScriptDOM – that’s one way if you prefer.
In my personal opinion, the easiest way to correlate is to examine the AST obtained by parsing a relevant / sample T-SQL fragment. You can use an approach like what I had blogged at https://deep.data.blog/2013/10/30/xml-visualizer-for-the-transactsql-scriptdom-ast/ to reverse engineer the tree.
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