sql如何合并多个表中的数据
SQL 列不同的表查询结果合并操作两个不同的表进行查询，需要把结果合并，
比如table1的列为 id, user_id, type_id,pro_id；
table2的列为 id,user_id,collect_id；分别如下图所示
table1：
table2：
将两个表的查询结果合并到一起的查询语句为
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select *, null as collect_id from table1 where user_id = 527unionselect id,user_id,null as type_id,null as pro_id, collect_id from table2 where user_id = 527; |
结果为：
其实就是把对应的列补充到没有该列的表中，在例子中就是把collect_id补充到table1中,
把type_id,pro_id补充到table2中。
补充知识：sql结果集合并用union all 不同表的列合并用join
结果集合并用union all 不同表的列合并用join
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SELECT"模块名","事件编码","点击数量","使用时长（单位：分）"FROM(SELECTT.fun_name as "模块名",T.event_code as "事件编码",SUM(click_records) as "点击数量"FROM(SELECT m.* FROM default.daily_new_clientrpt_master m WHERE event_id in ( SELECT max(event_id) AS "事件" from default.daily_new_clientrpt_master group by user_name,fun_code ORDER BY "事件" DESC ) ) T where day = today() GROUP BY "模块名" ,"事件编码") T5JOIN(SELECTT.fun_name as "模块名",T.event_code as "事件编码",round(sum(stay_time)/60000,0) as "使用时长（单位：分）"FROM(SELECT m.* FROM default.daily_new_clientrpt_master m WHERE event_id in ( SELECT "事件" FROM ( SELECT max(event_id) AS "事件", max(stay_time) AS "事件1" from default.daily_new_clientrpt_master group by user_name,fun_code ORDER BY "事件1" DESC) )) T where day = today() AND like(event_code,'%10000') GROUP BY "模块名" ,"事件编码") T6 ON T5."模块名"=T6."模块名" AND T5."事件编码"=T6."事件编码" |
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原文链接：https://blog.csdn.net/u010498402/article/details/78038553