Oracle SQL-将客户队列分配给员工列表

Question

我需要将员工名单分发给客户。

例如：

表1：员工名单：A，B和C

表2：客户列表：1、2、3、4、5、6、7、8、9

所需的结果：

| ------------ | ------------ |||客户|员工|| ------------ | ------------ ||| 1 | A || 2 | B || 3 | C || 4 | A || 5 | B || 6 | C || 7 | A || 8 | B || 9 | C || ------------ | ------------ ||

Answer 1

您可以使用ROW_NUMBER()即时为员工分配一个号码，并使用MOD()进行滚动加入。例如：

select
  c.id,
  e.name
from (
  select t.*,
    row_number() over(order by name) as rn
  from employees t
) e
join customers c on e.rn = 
  mod(rn, (select count(*) from customers)) + 1

Answer 2

对所有行编号，然后对联接使用模函数：

with e as
(
  select employee, row_number() over (order by employee) as rn
  from employees
)
, c as
(
  select customer, row_number() over (order by customer) as rn
  from customers
)
select c.customer, e.employee
from c
join e on e.rn - 1 = mod(c.rn - 1, (select count(*) from e))
order by c.customer;

演示：https://dbfiddle.uk/?rdbms=oracle_18&fiddle=43a6ca7469dff023d5513fa209e33ea7

Answer 3

您可以为此目的使用MOD功能。尝试下面的代码。

CREATE TABLE EMP
AS
   SELECT 'A' AS EMP FROM DUAL
   UNION ALL
   SELECT 'B' AS EMP FROM DUAL
   UNION ALL
   SELECT 'C' AS EMP FROM DUAL;

CREATE TABLE CUST
AS
   SELECT '1' AS CUST FROM DUAL
   UNION ALL
   SELECT '2' AS CUST FROM DUAL
   UNION ALL
   SELECT '3' AS CUST FROM DUAL
   UNION ALL
   SELECT '4' AS CUST FROM DUAL
   UNION ALL
   SELECT '5' AS CUST FROM DUAL
   UNION ALL
   SELECT '6' AS CUST FROM DUAL
   UNION ALL
   SELECT '7' AS CUST FROM DUAL
   UNION ALL
   SELECT '8' AS CUST FROM DUAL
   UNION ALL
   SELECT '9' AS CUST FROM DUAL;

  SELECT CUST, EMP
    FROM (SELECT ROW_NUMBER () OVER (PARTITION BY 1 ORDER BY EMP) AS ID, EMP
            FROM EMP) EMP
         INNER JOIN CUST ON MOD (TO_NUMBER (CUST.CUST) - 1, 3) = EMP.ID - 1
ORDER BY 1;