loop through azure objects and filter them on tags

Question

I have a question , recently we started using Tagging in Azure and needed to list specific object by thier Tags. Below is the script used to find the resources. in both cases we find a specific object in the results when using match and notmatch. This is strange behaviour when searching Tagged resources. what other ways do you use to complete the task?

PS C:\WINDOWS\system32> $KeyName = 'Department'
PS C:\WINDOWS\system32> $NewKeyValue = "PROD, Data"
PS C:\WINDOWS\system32> $AzSqlServer = Get-AzSqlServer
PS C:\WINDOWS\system32>          if($AzSqlServer)
>>     {
>> foreach ($server in $AzSqlServer )
>> {
>> $SQLDatabase = Get-AzSqlDatabase -ServerName $server.ServerName -ResourceGroupName $server.ResourceGroupName| Where-Object {$_.tags.Values -notmatch "PROD, Data"}
>> write-output $SQLDatabase.DatabaseName
>> }
>> }
DBname1
DBname2
DBname3
DBname4
master
master
master
**DBname5**
PS C:\WINDOWS\system32>
PS C:\WINDOWS\system32> $KeyName = 'Department'
PS C:\WINDOWS\system32> $NewKeyValue = "PROD, Data"
PS C:\WINDOWS\system32> $AzSqlServer = Get-AzSqlServer
PS C:\WINDOWS\system32>          if($AzSqlServer)
>>     {
>> foreach ($server in $AzSqlServer )
>> {
>> $SQLDatabase = Get-AzSqlDatabase -ServerName $server.ServerName -ResourceGroupName $server.ResourceGroupName| Where-Object {$_.tags.Values -match "PROD, Data"}
>> write-output $SQLDatabase.DatabaseName
>> }
>> }
**DBname5**

Answer 1

The problem here is with unexpected results of using -notmatch and -match operators against a list. Switching to -notcontains and -contains for exact matches will produce the desired result.

$AzSqlServer = Get-AzSqlServer
if ($AzSqlServer) {
    foreach ($server in $AzSqlServer) {
        $SQLDatabase = Get-AzSqlDatabase -ServerName $server.ServerName -ResourceGroupName $server.ResourceGroupName |
            Where-Object {$_.tags.Values -notcontains "PROD, Data"}
        $SQLDatabase.Databasename
    }
}

---

When using -notcontains, a list's items are compared in their entirety. The list will only return true if there are no items that match the target item. When using -notmatch against a list, the list's items that do not match the target item are returned. Any returned item results in a True result in a boolean statement. Below is a simplified example of your experience:

# Notice how both boolean statements return True
PS> 1,2,3 -notmatch 2
1
3
PS> [bool](1,2,3 -notmatch 2)
True
PS> 1,2,3 -match 2
2
PS> [bool](1,2,3 -match 2)
True

# Now using -notcontains and -contains
PS> 1,2,3 -notcontains 2
False
PS> 1,2,3 -contains 2
True