SQL Server has Microsoft Defender for SQL enabled

resource "azurerm_mssql_server_security_alert_policy" "<example_resource_name>" {
  server_id = "<example_resource_id>"
  state     = "Enabled" # Critical: enables the server's security alert policy (Defender for SQL)
}

param serverName string = '<example_resource_name>'

resource securityAlert 'Microsoft.Sql/servers/securityAlertPolicies@2021-11-01' = {
  name: '${serverName}/Default'
  properties: {
    state: 'Enabled' // Critical: enables the server's security alert policy (Defender for SQL)
  }
}