ORACLE多表关联UPDATE语句的语法

1）最简单的形式

update customers a    //使用别名

set customer_type='01'    //01 为vip，00为普通

where exists (select 1 from tmp_cust_city b where b.customer_id=a.customer_id)

2）两表(多表)关联update，被修改值由另一个表运算而来

update customers a     //使用别名

set city_name=(select b.city_name from tmp_cust_city b where b.customer_id=a.customer_id)

where exists (select 1 from tmp_cust_city b where b.customer_id=a.customer_id)

3） update 超过2个值

update customers a    //使用别名

set (city_name,customer_type)=(select b.city_name,b.customer_type from tmp_cust_city b where b.customer_id=a.customer_id)

where exists (select 1from tmp_cust_city b where b.customer_id=a.customer_id)