SELECT [WS_ID] , ISNULL(MAX(CASE WHEN [NODE_ID] = ‘Go‘ THEN STEP_ID WHEN [NODE_ID] = ‘Dispose‘ THEN STEP_ID ELSE NULL END), MAX([STEP_ID])) FROM [WS_INST_STEP] GROUP BY [WS_ID];
分组后条件查询
原文：https://www.cnblogs.com/myloveblogs/p/13360919.html
