functions/Get-DbaLastBackup.ps1

function Get-DbaLastBackup {
    <#
.SYNOPSIS
Get date/time for last known backups
 
.DESCRIPTION
Retrieves and compares the date/time for the last known backups, as well as the creation date/time for the database.
 
Default output includes columns Server, Database, RecoveryModel, LastFullBackup, LastDiffBackup, LastLogBackup, SinceFull, SinceDiff, SinceLog, Status, DatabaseCreated, DaysSinceDbCreated.
 
.PARAMETER SqlInstance
The SQL Server that you're connecting to.
 
.PARAMETER SqlCredential
Credential object used to connect to the SQL Server as a different user
 
.PARAMETER Database
The database(s) to process - this list is auto-populated from the server. If unspecified, all databases will be processed.
 
.PARAMETER ExcludeDatabase
The database(s) to exclude - this list is auto-populated from the server
 
.NOTES
Tags: DisasterRecovery, Backup
Author: Klaas Vandenberghe ( @PowerDBAKlaas )
 
Website: https://dbatools.io
Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
.LINK
 https://dbatools.io/Get-DbaLastBackup
 
.EXAMPLE
Get-DbaLastBackup -SqlInstance ServerA\sql987
 
Returns a custom object displaying Server, Database, RecoveryModel, LastFullBackup, LastDiffBackup, LastLogBackup, SinceFull, SinceDiff, SinceLog, Status, DatabaseCreated, DaysSinceDbCreated
 
.EXAMPLE
Get-DbaLastBackup -SqlInstance ServerA\sql987
 
Returns a custom object with Server name, Database name, and the date the last time backups were performed
 
.EXAMPLE
Get-DbaLastBackup -SqlInstance ServerA\sql987 | Select *
 
Returns a custom object with Server name, Database name, and the date the last time backups were performed, and also recoverymodel and calculations on how long ago backups were taken and what the status is.
 
.EXAMPLE
Get-DbaLastBackup -SqlInstance ServerA\sql987 | Select * | Out-Gridview
 
Returns a gridview displaying Server, Database, RecoveryModel, LastFullBackup, LastDiffBackup, LastLogBackup, SinceFull, SinceDiff, SinceLog, Status, DatabaseCreated, DaysSinceDbCreated
 
#>

    [CmdletBinding()]
    param (
        [parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [Alias("Credential")]
        [PSCredential]
        $SqlCredential,
        [Alias("Databases")]
        [object[]]$Database,
        [object[]]$ExcludeDatabase
    )

    process {
        foreach ($instance in $SqlInstance) {
            Write-Verbose "Connecting to $instance"
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $sqlcredential
            }
            catch {
                Write-Warning "Can't connect to $instance"
                Continue
            }

            $dbs = $server.Databases | Where-Object { $_.name -ne 'TempDb' }

            if ($Database) {
                $dbs = $dbs | Where-Object Name -In $Database
            }

            if ($ExcludeDatabase) {
                $dbs = $dbs | Where-Object Name -NotIn $ExcludeDatabase
            }

            foreach ($db in $dbs) {
                $result = $null
                Write-Verbose "Processing $db on $instance"

                if ($db.IsAccessible -eq $false) {
                    Write-Warning "The database $db on server $instance is not accessible. Skipping database."
                    Continue
                }
                # To avoid complicated manipulations on datetimes depending on locale settings and culture,
                # dates are compared to 0, which represents 1/01/0001 0:00:00
                $SinceFull = if ($db.LastBackupdate -eq 0) { "" }
                else { (New-TimeSpan -Start $db.LastBackupdate).Tostring() }
                $SinceFull = if ($db.LastBackupdate -eq 0) { "" }
                else { $SinceFull.split('.')[0 .. ($SinceFull.split('.').count - 2)] -join ' days ' }

                $SinceDiff = if ($db.LastDifferentialBackupDate -eq 0) { "" }
                else { (New-TimeSpan -Start $db.LastDifferentialBackupDate).Tostring() }
                $SinceDiff = if ($db.LastDifferentialBackupDate -eq 0) { "" }
                else { $SinceDiff.split('.')[0 .. ($SinceDiff.split('.').count - 2)] -join ' days ' }

                $SinceLog = if ($db.LastLogBackupDate -eq 0) { "" }
                else { (New-TimeSpan -Start $db.LastLogBackupDate).Tostring() }
                $SinceLog = if ($db.LastLogBackupDate -eq 0) { "" }
                else { $SinceLog.split('.')[0 .. ($SinceLog.split('.').count - 2)] -join ' days ' }

                $daysSinceDbCreated = (New-TimeSpan -Start $db.createDate).Days

                if ($daysSinceDbCreated -lt 1 -and $db.LastBackupDate -eq 0) { $Status = 'New database, not backed up yet' }
                elseif ((New-TimeSpan -Start $db.LastBackupDate).Days -gt 0 -and (New-TimeSpan -Start $db.LastDifferentialBackupDate).Days -gt 0) { $Status = 'No Full or Diff Back Up in the last day' }
                elseif ($db.RecoveryModel -eq "Full" -and (New-TimeSpan -Start $db.LastLogBackupDate).Hours -gt 0) { $Status = 'No Log Back Up in the last hour' }
                else { $Status = 'OK' }

                $result = [PSCustomObject]@{
                    ComputerName       = $server.NetName
                    InstanceName       = $server.ServiceName
                    SqlInstance        = $server.DomainInstanceName
                    Database           = $db.name
                    RecoveryModel      = $db.recoverymodel
                    LastFullBackup     = if ($db.LastBackupdate -eq 0) { $null } else { $db.LastBackupdate.tostring() }
                    LastDiffBackup     = if ($db.LastDifferentialBackupDate -eq 0) { $null } else { $db.LastDifferentialBackupDate.tostring() }
                    LastLogBackup      = if ($db.LastLogBackupDate -eq 0) { $null } else { $db.LastLogBackupDate.tostring() }
                    SinceFull          = $SinceFull
                    SinceDiff          = $SinceDiff
                    SinceLog           = $SinceLog
                    DatabaseCreated    = $db.createDate
                    DaysSinceDbCreated = $daysSinceDbCreated
                    Status             = $status
                    }
                Select-DefaultView -InputObject $result -Property ComputerName, InstanceName, SqlInstance, Database, LastFullBackup, LastDiffBackup, LastLogBackup
            }
        }
    }
}