sub_query join drupal7 view_query_alter
views里面添加 表达式 expressionhttps://www.drupal.org/docs/7/api/database-api/dynamic-queries/expressionsselect max 最大值https://blog.csdn.net/xx_star1204/article/details/88187631https://www.drupal.org/forum/support/module-development-and-code-questions/2009-03-22/implementing-custom-sql-query-for$sub_query = db_select('workflow_node_history', 'sub_workflow_node_history_states'); $sub_query->addField('sub_workflow_node_history_states', 'nid'); $sub_query->addField('sub_workflow_states', 'weight', 'weight'); $sub_query->addField('sub_workflow_states_old', 'weight' , 'old_weight'); $sub_query->addJoin(