SQuirreL is a powerful open source graphical application that you can install on your computer to connect to your LeanXcale instance and write, edit and execute SQL statements, edit the result-sets and much more. You can check the documentation about installing and configuring SQuirreL here.
lxClient is a simple command line SQL client bundled with LeanXcale, so it can only be used in On Premise configurations. If you’re using the Cloud version of LeanXcale, you can use a limited version of lxClient by going to Data > Run SQL inside each one of your instances.
You can check the documentation for lxClient here.