随机选择多条记录

Question

I have a table with both Male & Female genders (PK (Id), PersonsName, IsMale). I wish to get a random name but for both genders. Example:

Select Top 1 PersonsName 
From MyTable 
Where IsMale = '1' 
Order by NewID()

Select Top 1 PersonsName 
From MyTable 
Where IsMale = '0' 
Order by NewID()

How can I combine those statements so I return 2 records (1 male and 1 female name) from the one SQL statement?

I have seen on here in the past that someone just separated the two statements in the same SQL query, like so:

Select Top 1 PersonsName 
From MyTable 
Where IsMale = '1' 
Order by NewID();

Select Top 1 PersonsName 
From MyTable 
Where IsMale = '0' 
Order by NewID()

Each time the code is run I wish to have two totally random names and not two records of the same gender so I can populate the dataset and bind it to a ListView control. I just need the SQL statement

Answer 1

What you are looking for is the UNION keyword

select PersonsName from (Select TOP 1 PersonsName From MyTable Where IsMale = '1' Order by NewID()) a
UNION ALL
Select PersonsName from (Select TOP 1 PersonsName From MyTable Where IsMale = '0' Order by NewID()) b

This will return 1 result set with 2 rows.

Answer 2

You can also use Row_Number() and the WITH TIES clause. This will return one of each.

Select Top 1 with Ties *
 From  YourTable
 Order By Row_Number() over (Partition By IsMale Order by NewID())

On a side-note. Top 4 will give you two of each

Answer 3

Use union keyword for avoiding same duplicates records. Union is a keyword, use for writing two sql query which return same type of records with same number of columns(columns names can be differ but alias should me same for two queries).

Select Top 1 PersonsName From MyTable Where IsMale = '1' Order by NewID() union Select Top 1 PersonsName From MyTable Where IsMale = '0' Order by NewID()