[英]How to self joining table from following scenario?
Consider I have a table named table1 which contains following data:考虑我有一个名为 table1 的表,其中包含以下数据:
id, value
1, a
1, b
1, c
1, d
2, a
2, b
2, c
3, b
3, c
4, a
4, b
4, c
4, d
I wanted to select all ids that have a value = d.我想选择所有值为 d 的 ID。 How could I achieve this?
我怎么能做到这一点?
Which means I need to get the result of ( 1 and 4 ) , since id 2 and 3 do not contain d.这意味着我需要得到 ( 1 和 4 ) 的结果,因为 id 2 和 3 不包含 d。
the actual table contains more than 10,000,000 rows, so the query should not be too slow.实际表包含超过 10,000,000 行,因此查询不应太慢。
Thanks for your ideas.谢谢你的想法。
This should be pretty straight forward.这应该很简单。 ( There is no need for join )
(不需要加入)
SELECT *
FROM TableName
WHERE value = 'd'
You don't need a join at all:您根本不需要加入:
SELECT id
FROM myTable
WHERE value = 'd'
Try this尝试这个
select id
from Table1
where value= 'd'
Please Try this query it will help you请试试这个查询它会帮助你
select * from table1 t, table1 t1
where t.value = t1.value and t1.value='d'
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