标签：you tab span into 通过 行数据 标识 div value
数据说明：table1的数据是 客户id，基金差额，保险差额，理财差额，。。。
create table youhua1( -> custid int -> ,jijin_change float -> ,baoxian_change float -> ,cunkuan_change float) -> ; insert into youhua1 values(1,1.1,1.2,1.3),(2,2.67,2.34,2.1),(3,3.1,3.4,3.78); select * from youhua1; +--------+--------------+----------------+----------------+ | custid | jijin_change | baoxian_change | cunkuan_change | +--------+--------------+----------------+----------------+ | 1 | 1.1 | 1.2 | 1.3 | | 2 | 2.67 | 2.34 | 2.1 | | 3 | 3.1 | 3.4 | 3.78 | +--------+--------------+----------------+----------------+
原查询思路：
select custid ,"基金" as prod_name ,jijin_change as 差额 from youhua1 union all select custid ,"保险" as prod_name ,baoxian_change 差额 from youhua1 union all select custid ,"存款" as prod_name ,cunkuan_change as 差额 from youhua1;
目标数据：客户1，基金，差额(基金)
客户1，保险，差额(保险)
...
+--------+-----------+------+ | custid | prod_name | 差额 | +--------+-----------+------+ | 1 | 基金 | 1.1 | | 2 | 基金 | 2.67 | | 3 | 基金 | 3.1 | | 1 | 保险 | 1.2 | | 2 | 保险 | 2.34 | | 3 | 保险 | 3.4 | | 1 | 存款 | 1.3 | | 2 | 存款 | 2.1 | | 3 | 存款 | 3.78 | +--------+-----------+------+
优化方案：
当数据量很大时，这种方式会造成多次读表。
可以采用from前置的方式;
也可以先通过concat函数拼接jijin_change、baoxian_change、cunkuan_change三个字段成一列，然后再用列转行函数lateral view explode函数处理。
行转列：一个字段的多行数据合进一个列；列转行：一个字段的一列数据拆到多个行
select custid,concat_ws(‘,‘,jijin_change,baoxian_change,cunkuan_change) from youhua1; +--------+-----------------------------------------------------------+ | custid | concat_ws(‘,‘,jijin_change,baoxian_change,cunkuan_change) | +--------+-----------------------------------------------------------+ | 1 | 1.1,1.2,1.3 | | 2 | 2.67,2.34,2.1 | | 3 | 3.1,3.4,3.78 | +--------+-----------------------------------------------------------+
select a.custid ,change from ( select custid ,concat_ws(‘,‘,jijin_change,baoxian_change,cunkuan_change) as all_change from youhua1 ) as a lateral view explode(split(a.all_change)) table_tmp as change;
没有加上基金、保险、存款的行标识：
可以在concat_ws之前先将基金、保险、存款的行标识和值打在一起，concat_ws("+","基金"+"jijin_change")，...
在explode时指定split(a.all_change, ‘,‘)，最后select custid,split(change,"+")[0] as prod_name,split(change,"+")[1] as change
标签：you tab span into 通过 行数据 标识 div value
原文地址：https://www.cnblogs.com/foolangirl/p/14145147.html
