Extract Hot Fix Details from a SQL Server CU KB Articles

<#
.SYNOPSIS
Retrieve Details of SQL Server KB change log
 
.DESCRIPTION
Get-SQLCUDetail is to extract the summary of changes described in SQL Server KB for a CU
This is more for CU KBs released after Mar, 2014, because in these CU KB article, there is new column [fixe area], 
indicating to what service the fix is applicable, such as wheter it is SSAS or SSRS or SQL Service etc.
 
.Parameter
-SQLCU_Url weblink to the CU KB, it is mandatory
 
.PARAMETER
-TableNumber indicates which table in the SQLCU_Url website shall we extract the SQL KB info,
the table number is 0 based, and defaults to 0. Not mandatory
 
.PARAMETER
-IncludeLink a switch parameter, if exists, will extract the HREF link out of the table column value, 
we assume there is only one column has HREF link.
 
.EXAMPLE
The following returns the fix summary of SQL Server 2017 CU4 for RTM
Get-SQLCUDetail -SQLCU 'https://support.microsoft.com/en-us/help/4056498/cumulative-update-4-for-sql-server-2017' | 
select 'kb article number', 'fix area', 'description' | ft -auto -wrap
 
KB article number Fix area                Description                                              
----------------- --------                -----------                                              
4042948           Reporting Services      FIX: Data-driven subscription fails after you upgrade    
                                          from SSRS 2008 to SSRS 2016                              
4053550           SQL Engine              FIX: Processing XML message through Service Broker       
                                          results in hung session in SQL Server 2016 and 2017      
4052123           Reporting Services      FIX: Sliding expiration for authentication cookie isn't  
                                          working and fails to redirect to logon page in SSRS 2016 
                                          and 2017                                                 
4057054           SQL performance         FIX: CXPACKET and CXCONSUMER wait types show             
                                          inconsistent results for some parallel query plans in    
                                          SQL Server 2017                                          
4057087           SQL Engine              FIX: Unable to restore a database using replace option   
                                          if the FILENAME contains double slash operator in SQL    
                                          Server 2017                                              
4076982           High Availability       FIX: Pacemaker demotes existing primary replica of an    
                                          AlwaysOn AG in SQL Server 2017 on Linux and never        
                                          promotes a new one                                       
4077103           In-Memory OLTP          FIX: In-Memory databases in an Availability Group hang   
                                          during recovery in SQL Server 2017                       
4077683           SQL Engine              FIX: System stored procedure sp_execute_external_script  
                                          and DMV sys.dm_exec_cached_plans cause memory leaks in   
                                          SQL Server 2017                                          
4055727           In-Memory OLTP          FIX: Recovery of database takes a long time when it      
                                          contains memory-optimized tables in SQL Server 2016 and  
                                          2017                                                     
4053439           SQL Engine              Improvement: Move master database and error log file to  
                                          another location in SQL Server 2017 on Linux             
4057759           Analysis Services       FIX: Internal error when you drill down hierarchy        
                                          members in SSAS 2016 and 2017 in multidimensional mode   
..... 
#>
 
function Get-SQLCUDetail
{
    [cmdletbinding()]
    param(
        [Parameter(Mandatory = $true)]
        [string]$SQLCU_Url, 
 
        [Parameter(Mandatory = $false)]
        [int] $TableNumber=0, # 0 based,
 
        [Parameter(Mandatory=$false)]
        [switch] $IncludeLink
    )
 
    try
    {
        $iex = new-object -ComObject "InternetExplorer.Application";
        $iex.silent = $true;
        $iex.navigate($SQLCU_Url);
        while($iex.Busy) { Start-Sleep -Milliseconds 200; }
        Start-Sleep 1; #adjust 1 to higher number if your computer or internet speed connection is slow
 
        $tables =@($iex.Document.documentElement.getElementsByTagName('table'));
        if ($tables -eq $null -or $tables.count -eq 0)
        {
            throw {"this $SQLCU_URL is not a valid SQL CU URL"};
        }
 
        $table = $tables[$TableNumber];
        $titles = @();
        $dt = new-object System.Data.DataTable;
 
        $rows = @($table.Rows);
 
        ## Go through all of the rows in the table
        foreach($row in $rows)
        {
            $cells = @($row.Cells)
            ## If we've found a table header, remember its titles
            if($cells[0].tagName -eq "TH")
            {
                $titles = @($cells | % { ($_.InnerText).Trim(); });
                continue;
            }
 
            ## If we haven't found any table headers, make up names "P1", "P2", etc.
            if(-not $titles)
            {
                $titles = @(1..($cells.Count + 2) | % { "P$_" })
            }
            if ($dt.Columns.Count -eq 0)
            {
                foreach ($title in $titles)
                {
                    $col = New-Object System.Data.DataColumn($title, [System.String]);
                    $dt.Columns.Add($col);
                }
                if ($IncludeLink)
                {  
                    $col = New-Object System.Data.DataColumn('URL', [System.String]);
                    $dt.Columns.Add($col);
                }
 
            } #if $dt.columns.count -eq 0
 
            $dr = $dt.NewRow();
            for($counter = 0; $counter -lt $cells.Count; $counter++)
            {
                $c = $cells[$counter];
                $title = $titles[$counter];
                if(-not $title) { continue; }
                $dr.$title = ("" + $c.InnerText).Trim();
 
               if ($IncludeLink)
                {
                    if ($c.getElementsByTagName('a').length -gt 0)
                    {
                      $dr.URL = ($c.getElementsByTagName('a') | select -ExpandProperty href) -join ';';
                    }
                }
            }
            $dt.Rows.add($dr);
        } #foreach
 
        #add the CU link to the $dt table 
        $col =  New-Object System.Data.DataColumn('SQLCU_URL', [System.String]);
        $col.DefaultValue = $SQLCU_Url;
        $dt.columns.Add($col);
 
        Write-Output $dt -NoEnumerate;
    }#try
    catch
    {
        Write-Error $_;
    }
    $iex.Stop();
    $iex.Quit();
}#Get-SQLCUDetail