What is the invoice number and invoice date corresponding to the invoice with the greatest number of transactions?
SELECT T2.invoice_number ,  T2.invoice_date FROM Financial_transactions AS T1 JOIN Invoices AS T2 ON T1.invoice_number  =  T2.invoice_number GROUP BY T1.invoice_number ORDER BY count(*) DESC LIMIT 1
SELECT T2.invoice_number ,  T2.invoice_date FROM Financial_transactions AS T1 JOIN Invoices AS T2 ON T1.invoice_number  =  T2.invoice_number GROUP BY T1.invoice_number ORDER BY count(*) DESC LIMIT 1
[{'invoice_number': 12, 'invoice_date': '2018-03-15 21:24:13'}]