From the passage provided, extract the acquisition details of Tableau.

Tableau Software (/tæbˈloʊ/ tab-LOH) is an American interactive data visualization software company focused on business intelligence.[1][2] It was founded in 2003 in Mountain View, California, and is currently headquartered in Seattle, Washington.[3] In 2019 the company was acquired by Salesforce for $15.7 billion.[4] At the time, this was the largest acquisition by Salesforce (a leader in the CRM field) since its foundation.[5] It was later surpassed by Salesforce's acquisition of Slack.[6]

The company's founders, Christian Chabot, Pat Hanrahan and Chris Stolte, were researchers at the Department of Computer Science at Stanford University.[7] They specialized in visualization techniques for exploring and analyzing relational databases and data cubes,[8] and started the company as a commercial outlet for research at Stanford from 1999 to 2002.

Tableau products query relational databases, online analytical processing cubes, cloud databases, and spreadsheets to generate graph-type data visualizations. The software can also extract, store, and retrieve data from an in-memory data engine.

Tableau was acquired in 2019 by Salesforce for $15.7 billion.