Question: Recently I have migrated my test site from `windows classic` to `claim based authentication`. Before doing the same in production, how to check if my site collection is working fine? What are the potential issues that we may face after changed authentication modelto `claims` from `classic`? The Site contains a number of groups, workflows etc.. Any suggestion will be highly appreciated.

Answer: 
Get the CAML query of ANY VIEW by following PowerShell 

```
$spWeb = Get-SPWeb -Identity "Site URL goes here";
$spList = $spWeb.Lists["List Name"];
$spView = $spList.Views["View Name"];
$spView.Query | Out-File "Path with file name"

```

**or**

Make a GET request to following end-point using any rest client 

```
http://Site URL/_api/Web/Lists/getbytitle('List Name')/Views/getbytitle('View Name')?$select=ViewQuery

```

Learn [more](http://www.codeproject.com/Articles/993035/Building-CAML-for-querying-List-in-SharePoint)
I don't really understand the question, but if you want to query a list for items in specific columns depending on different circumstances, you should use CAMLQuery

[U2U CAMLQuery helper](http://www.u2u.be/Software) is a nice tool to get started.