Make SQL Select same row multiple times

I need to test my mail server. How can I make a Select statement that selects say ID=5469 a thou开发者_JS百科sand times.

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If I get your meaning then a very simple way is to cross join on a derived query on a table with more than 1000 rows in it and put a top 1000 on that. This would duplicate your results 1000 times.

EDIT: As an example (This is MSSQL, I don't know if Access is much different)

SELECT
    MyTable.*
FROM
    MyTable
CROSS JOIN
(
    SELECT TOP 1000
        *
    FROM
        sysobjects
) [BigTable]
WHERE
    MyTable.ID = 1234

---

You can use the UNION ALL statement.

Try something like:

SELECT * FROM tablename WHERE ID = 5469
UNION ALL
SELECT * FROM tablename WHERE ID = 5469

You'd have to repeat the SELECT statement a bunch of times but you could write a bit of VB code in Access to create a dynamic SQL statement and then execute it. Not pretty but it should work.

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Create a helper table for this purpose:
JUST_NUMBER(NUM INT primary key)
Insert (with the help of some (VB) script) numbers from 1 to N. Then execute this unjoined query:

SELECT  MYTABLE.*
FROM    MYTABLE,
        JUST_NUMBER
WHERE   MYTABLE.ID = 5469 
    AND JUST_NUMBER.NUM <= 1000

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Here's a way of using a recursive common table expression to generate some empty rows, then to cross join them back onto your desired row:

declare @myData table (val int) ;
insert @myData values (666),(888),(777) --some dummy data

;with cte as
(
    select 100 as a
    union all
    select a-1 from cte where a>0 
        --generate 100 rows, the max recursion depth

)
,someRows as
(
select top 1000 0 a from cte,cte x1,cte x2 
       --xjoin the hundred rows a few times
       --to generate 1030301 rows, then select top n rows
)
select m.* from @myData m,someRows where m.val=666

substitute @myData for your real table, and alter the final predicate to suit.

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easy way...

This exists only one row into the DB

sku = 52 , description = Skullcandy Inkd Green ,price = 50,00

Try to relate another table in which has no constraint key to the main table

Original Query

SELECT  Prod_SKU , Prod_Descr , Prod_Price FROM  dbo.TB_Prod WHERE Prod_SKU = N'52'

The Functional Query ...adding a not related table called 'dbo.TB_Labels'

SELECT TOP ('times')  Prod_SKU , Prod_Descr , Prod_Price FROM  dbo.TB_Prod,dbo.TB_Labels WHERE Prod_SKU = N'52'

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In postgres there is a nice function called generate_series. So in postgreSQL it is as simple as:

select information from test_table, generate_series(1, 1000) where id = 5469

In this way, the query is executed 1000 times.

Example for postgreSQL:

CREATE EXTENSION IF NOT EXISTS "uuid-ossp"; --To be able to use function uuid_generate_v4()

--Create a test table
create table test_table (
   id serial not null,
   uid UUID NOT NULL,
   CONSTRAINT uid_pk PRIMARY KEY(id));

-- Insert 10000 rows
insert into test_table (uid) 
select uuid_generate_v4() from generate_series(1, 10000);

-- Read the data from id=5469 one thousand times
select id, uid, uuid_generate_v4() from test_table, generate_series(1, 1000) where id = 5469;

As you can see in the result below, the data from uid is read 1000 times as confirmed by the generation of a new uuid at every new row.

 id  |uid                                   |uuid_generate_v4
 ----------------------------------------------------------------------------------------
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"5630cd0d-ee47-4d92-9ee3-b373ec04756f"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"ed44b9cb-c57f-4a5b-ac9a-55bd57459c02"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"3428b3e3-3bb2-4e41-b2ca-baa3243024d9"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"7c8faf33-b30c-4bfa-96c8-1313a4f6ce7c"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"b589fd8a-fec2-4971-95e1-283a31443d73"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"8b9ab121-caa4-4015-83f5-0c2911a58640"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"7ef63128-b17c-4188-8056-c99035e16c11"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"5bdc7425-e14c-4c85-a25e-d99b27ae8b9f"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"9bbd260b-8b83-4fa5-9104-6fc3495f68f3"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"c1f759e1-c673-41ef-b009-51fed587353c"
 5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"4a70bf2b-ddf5-4c42-9789-5e48e2aec441"

Of course other DBs won't necessarily have the same function but it could be done:

See here.

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If your are doing this in sql Server

declare @cnt int
set @cnt = 0

while @cnt < 1000
begin
    select '12345'
    set @cnt = @cnt + 1
end 

select '12345' can be any expression

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Repeat rows based on column value of TestTable. First run the Create table and insert statement, then run the following query for the desired result. This may be another solution:

CREATE TABLE TestTable
(
 ID INT IDENTITY(1,1),
 Col1 varchar(10),
 Repeats INT
)

INSERT INTO TESTTABLE
VALUES ('A',2), ('B',4),('C',1),('D',0)

WITH x AS 
(
  SELECT TOP (SELECT MAX(Repeats)+1 FROM TestTable) rn = ROW_NUMBER() 
  OVER (ORDER BY [object_id]) 
  FROM sys.all_columns 
  ORDER BY [object_id]
)
SELECT * FROM x
CROSS JOIN TestTable AS d
WHERE x.rn <= d.Repeats 
ORDER BY Col1;

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This trick helped me in my requirement.

here, PRODUCTDETAILS is my Datatable and orderid is my column.

declare @Req_Rows int = 12

;WITH cte AS 
(
    SELECT 1 AS Number
    UNION ALL
    SELECT Number + 1 FROM cte WHERE Number < @Req_Rows
) 

SELECT PRODUCTDETAILS.* 

FROM cte, PRODUCTDETAILS 
WHERE PRODUCTDETAILS.orderid = 3

---

create table #tmp1 (id int, fld varchar(max))
insert into #tmp1 (id, fld) 
values (1,'hello!'),(2,'world'),(3,'nice day!')

select * from #tmp1
go

select * from #tmp1 where id=3
go 1000

drop table #tmp1

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in sql server try:

print 'wow'
go 5

output:

Beginning execution loop
wow
wow
wow
wow
wow
Batch execution completed 5 times.

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The easy way is to create a table with 1000 rows. Let's call it BigTable. Then you would query for the data you want and join it with the big table, like this:

SELECT MyTable.*
FROM MyTable, BigTable
WHERE MyTable.ID = 5469