[英]DISTINCT clause with WHERE
How can I use the DISTINCT clause with WHERE? 如何在WHERE中使用DISTINCT子句? For example:
例如:
SELECT * FROM table WHERE DISTINCT email; -- email is a column name
I want to select all columns from a table with distinct email addresses. 我想从具有不同电子邮件地址的表中选择所有列。
If you mean all columns whose email is unique: 如果您指的是其电子邮件唯一的所有列:
SELECT * FROM table WHERE email in
(SELECT email FROM table GROUP BY email HAVING COUNT(email)=1);
可能是:
SELECT DISTINCT email,id FROM table where id='2';
select t1.*
from YourTable as t1
inner join
(select email
from YourTable
group by email
having count(email) = 1 ) as t2
on t1.email = t2.email
You can use the HAVING
clause. 您可以使用
HAVING
子句。
SELECT *
FROM tab_name
GROUP BY email_id
HAVING COUNT(*) = 1;
One simple query will do it: 一个简单的查询就可以了:
SELECT *
FROM table
GROUP BY email
HAVING COUNT(*) = 1;
Wouldn't this work: 这不会起作用:
SELECT email FROM table1 t1
where UNIQUE(SELECT * FROM table1 t2);
简单查询此查询选择电子邮件唯一的表中的所有记录:
select distinct email,* from table_name
If you have a unique column in your table (eg tableid) then try this. 如果表中有一个唯一的列(例如tableid),那么试试这个。
SELECT EMAIL FROM TABLE WHERE TABLEID IN
(SELECT MAX(TABLEID), EMAIL FROM TABLE GROUP BY EMAIL)
Try: 尝试:
SELECT * FROM table GROUP BY email
You can use ROW_NUMBER(). 您可以使用ROW_NUMBER()。 You can specify where conditions as well.
您也可以指定条件。 (eg
Name LIKE'MyName%
in the following query) (例如,在以下查询中
Name LIKE'MyName%
)
SELECT *
FROM (SELECT ID, Name, Email,
ROW_NUMBER() OVER (PARTITION BY Email ORDER BY ID) AS RowNumber
FROM MyTable
WHERE Name LIKE 'MyName%') AS a
WHERE a.RowNumber = 1
SELECT DISTINCT dbo.Table.Email,dbo.Table.FirstName dbo.Table.LastName,dbo.Table.DateOfBirth(etc)FROM dbo.Table.Contacts WHERE Email ='name @ email';
查询:
Select *, (Select distinct email) from Table1
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.