Recently, various deep learning approaches have been proposed based on the WikiSQL dataset (Zhong et al., 2017).
because WikiSQL contains only very simple queries over just a single table, these approaches (Xu et al., 2017;Huang et al., 2018;Yu et al., 2018a;Dong and Lapata, 2018) cannot be applied directly to generate complex queries containing elements such as JOIN, GROUP BY, and nested queries.