從一個表中獲取所有ID，然后根據該表在另一個表中插入值

Question

我有兩個表：

表1：公司（id，名稱）表2：假期（id，companyId，名稱）

當前公司表中有數據，但節假日沒有。 我想遍歷所有公司，獲取其ID並在假期為每個公司插入兩條記錄。 因此，這將在之前和之后：

之前：

Companies
| id | name  |
|  0 | test1 |
|  1 | test2 |

假期： Empty table

后：

Companies
| id | name  |
|  0 | test1 |
|  1 | test2 |

Holidays:
| id | companyId | name     | 
|  0 |         0 | holiday1 |
|  1 |         0 | holiday2 |
|  2 |         1 | holiday1 |
|  3 |         1 | holiday2 |

Answer 1

假設Holidays.id設置為自動遞增：

insert into Holidays (select id as companyId, 'holiday1' as name from Companies);
insert into Holidays (select id as companyId, 'holiday2' as name from Companies);

Answer 2

您需要Companies表的自聯接和迭代邏輯來為Holidays生成id列值。 因此，請考慮使用：

insert into Holidays(id,company_id,name)
select @rn := @rn + 1, c1.id, concat('Holiday',(c1.id+1))
  from Companies c1
  join Companies c2
  join (select @rn := -1) as q_iter;

演示版

Answer 3

我想你要：

insert into holidays (companyId, name)
    select c.companyId, h.name
    from companies c cross join
         (select 1 as ord, 'holiday1' as name union all
          select 2 as ord, 'holiday2'
         ) h
    order by c.companyId, h.ord;

假定holidays.id是一個自動遞增的列。 如果沒有，則應使其成為一體。 如果沒有，則可以使用row_number() ：

insert into holidays (id, companyId, name)
    select row_number() over (order by c.companyId, h.ord),
           c.companyId, h.name
    from companies c cross join
         (select 1 as ord, 'holiday1' as name union all
          select 2 as ord, 'holiday2'
         ) h
    order by c.companyId, h.ord;

或參數：

insert into holidays (id, companyId, name)
    select (@rn := @rn + 1) as id,
           c.companyId, h.name
    from companies c cross join
         (select 1 as ord, 'holiday1' as name union all
          select 2 as ord, 'holiday2'
         ) h cross join
         (select @rn := 0) params
    order by c.companyId, h.ord;