Check SQL Server encryption certificates present without a backup issue using PowerShell

try
{
    $Error.Clear()
    #Open database
    $sqlConnection.Open()
}
catch [System.Data.SqlClient.SqlException]
{
    #Catch and throw the terminating exception
    throw $Error[0].Exception.Message
}
 
#Sql query statement to get all fragmented databases
$sqlQuery = "WITH EncryptedCertificates AS (SELECT a.name AS Database_Name,COALESCE(c.name, 'NA')AS Certificate_Name, CASE a.is_encrypted WHEN 1 THEN 'Encrypted' WHEN 0 THEN 'Not Encrypted' END AS Is_Encrypted,COALESCE(Cast(c.pvt_key_last_backup_date AS VARCHAR(50)), 'NA')AS Last_BackupDate FROM sys.databases a LEFT OUTER JOIN sys.dm_database_encryption_keys b ON a.database_id = b.database_id LEFT OUTER JOIN sys.certificates c ON b.encryptor_thumbprint = c.thumbprint JOIN sys.database_mirroring d ON d.database_id = a.database_id WHERE d.mirroring_guid IS NULL AND source_database_id IS NULL AND a.name NOT IN ( 'master', 'tempdb', 'model', 'msdb' )) SELECT * FROM EncryptedCertificates WHERE  last_backupdate = 'NA' AND certificate_name <> 'NA'"
 
#Create SqlDataAdapter object with command text and connection
$sqlDataTable = New-Object System.Data.DataTable
$oSQLAdapter = New-Object System.Data.SqlClient.SqlDataAdapter($sqlQuery,$sqlConnection)
$oSQLAdapter.Fill($sqlDataTable) | Out-Null
 
#Close SqlConnection
$sqlConnection.Close()

try 
{ 
    $Error.Clear() 
    #Open database$sqlConnection.Open() 
} 
catch [System.Data.SqlClient.SqlException] 
{ 
    #Catch and throw the terminating exceptionthrow$Error[0].Exception.Message 
} 
  
#Sql query statement to get all fragmented databases$sqlQuery = "WITH EncryptedCertificates AS (SELECT a.name AS Database_Name,COALESCE(c.name, 'NA')AS Certificate_Name, CASE a.is_encrypted WHEN 1 THEN 'Encrypted' WHEN 0 THEN 'Not Encrypted' END AS Is_Encrypted,COALESCE(Cast(c.pvt_key_last_backup_date AS VARCHAR(50)), 'NA')AS Last_BackupDate FROM sys.databases a LEFT OUTER JOIN sys.dm_database_encryption_keys b ON a.database_id = b.database_id LEFT OUTER JOIN sys.certificates c ON b.encryptor_thumbprint = c.thumbprint JOIN sys.database_mirroring d ON d.database_id = a.database_id WHERE d.mirroring_guid IS NULL AND source_database_id IS NULL AND a.name NOT IN ( 'master', 'tempdb', 'model', 'msdb' )) SELECT * FROM EncryptedCertificates WHERE  last_backupdate = 'NA' AND certificate_name <> 'NA'"#Create SqlDataAdapter object with command text and connection$sqlDataTable = New-Object System.Data.DataTable 
$oSQLAdapter = New-Object System.Data.SqlClient.SqlDataAdapter($sqlQuery,$sqlConnection) 
$oSQLAdapter.Fill($sqlDataTable) |Out-Null#Close SqlConnection$sqlConnection.Close()