I want Union of two queries with the first query resultset getting the first ten rownums in Oracle.
Example:
Like if first query has 10 rows and max rownum is 10.I want second query rownum to be started from 11 in the result of union.
SELECT *
FROM (
SELECT *
FROM table1
ORDER BY
col1
)
WHERE rownum <= 10
UNION ALL
SELECT *
FROM (
SELECT *, rownum AS rn
FROM (
SELECT *
FROM table2
ORDER BY
col2
)
)
WHERE rn > 10
Related
I want to write a query which will fetch me the first and last 3 records from the table
Below is the table details
select * from employee_src
Now to get the above result i am using the below query
select fname,lname,ssn,salary,dno from employee_src where rownum <=3
union all
select fname,lname,ssn,salary,dno from (select fname,lname,ssn,salary,dno from employee_src order by rownum desc) where rownum <=3
On running this query I am getting the below result
Even though I am getting the first 3 and last 3 rows but the last 3 rows are not in the order as in the original table. How to get this fixed.
Try this.
select * from (select * from employee_src order by rownum Asc) where rownum <= 3
union all
select *, from ( select * from employee_src from dual order by rownum desc
) as employee_src_last3
where rownum <= 3
Try now...
I have a table with columns 'Id' and 'Status'.
I want to write a SQL statement to select top 50 rows from this table with 25 rows with Status 1 and 25 rows with Status 2 in one SQL query.
I want my result to have rows with alternate status.
Please suggest me how to write this Query.
If you use MSSQL you can do this:
SELECT TOP 25
*
FROM
Table1
WHERE
Table1.Status=1
UNION ALL
SELECT TOP 25
*
FROM
Table1
WHERE
Table1.Status=2
If you use MYSQL you have to use LIMIT. Like this:
(
SELECT
*
FROM
Table1
WHERE
Table1.Status=1
LIMIT 25
)
UNION ALL
(
SELECT
*
FROM
Table1
WHERE
Table1.Status=2
LIMIT 25
);
For SQL Server, use TOP:
SELECT TOP 25 * FROM TableName WHERE Status=1
UNION ALL
SELECT TOP 25 * FROM TableName WHERE Status=2
For alternative result:
SELECT * FROM
(
SELECT TOP 25 *,ROW_NUMBER() OVER(ORDER BY Status) as RN FROM TableName WHERE Status=1
UNION ALL
SELECT TOP 25 *,ROW_NUMBER() OVER(ORDER BY Status) as RN FROM TableName WHERE Status=2
) T
ORDER BY RN
I tried the sql query given below:
SELECT * FROM (SELECT *
FROM TABLE_A ORDER BY COLUMN_1)DUMMY_TABLE
UNION ALL
SELECT * FROM TABLE_B
It results in the following error:
The ORDER BY clause is invalid in views, inline functions, derived
tables, subqueries, and common table expressions, unless TOP or FOR
XML is also specified.
I need to use order by in union all. How do I accomplish this?
SELECT *
FROM
(
SELECT * FROM TABLE_A
UNION ALL
SELECT * FROM TABLE_B
) dum
-- ORDER BY .....
but if you want to have all records from Table_A on the top of the result list, the you can add user define value which you can use for ordering,
SELECT *
FROM
(
SELECT *, 1 sortby FROM TABLE_A
UNION ALL
SELECT *, 2 sortby FROM TABLE_B
) dum
ORDER BY sortby
You don't really need to have parenthesis. You can sort directly:
SELECT *, 1 AS RN FROM TABLE_A
UNION ALL
SELECT *, 2 AS RN FROM TABLE_B
ORDER BY RN, COLUMN_1
Not an OP direct response, but I thought I would jimmy in here responding to the the OP's ERROR messsage, which may point you in another direction entirely!
All these answers are referring to an overall ORDER BY once the record set has been retrieved and you sort the lot.
What if you want to ORDER BY each portion of the UNION independantly, and still have them "joined" in the same SELECT?
SELECT pass1.* FROM
(SELECT TOP 1000 tblA.ID, tblA.CustomerName
FROM TABLE_A AS tblA ORDER BY 2) AS pass1
UNION ALL
SELECT pass2.* FROM
(SELECT TOP 1000 tblB.ID, tblB.CustomerName
FROM TABLE_B AS tblB ORDER BY 2) AS pass2
Note the TOP 1000 is an arbitary number. Use a big enough number to capture all of the data you require.
There will be times when you need to do something like this :
Pull top 5 from table 1 based on a sort
and bottom 5 from table 2 based on another sort
and union these together.
solution
select * from (
-- top 5 records
select top 5 col1, col2, col3
from table1
group by col1, col2
order by col3 desc ) z
union all
select * from (
-- bottom 5 records
select top 5 col1, col2, col3
from table2
group by col1, col2
order by col3 ) z
this was the only way i was able to get around the error and worked fine for me.
SELECT * FROM (SELECT *
FROM TABLE_A ORDER BY COLUMN_1)DUMMY_TABLE
UNION ALL
SELECT * FROM TABLE_B
ORDER BY 2;
2 is column number here .. In Oracle SQL you can use the column number by which you want to sort the data
This solved my SELECT statement:
SELECT * FROM
(SELECT id,name FROM TABLE_A
UNION ALL
SELECT id,name FROM TABLE_B ) dum
order by dum.id , dum.name
where id and name columns available in tables and you can use your columns .
Simply use that , no need parenthesis or anything else
SELECT *, id as TABLE_A_ID FROM TABLE_A
UNION ALL
SELECT *, id as TABLE_B_ID FROM TABLE_B
ORDER BY TABLE_A_ID, TABLE_B_ID
ORDER BY after the last UNION should apply to both datasets joined by union.
The solution shown below:
SELECT *,id AS sameColumn1 FROM Locations
UNION ALL
SELECT *,id AS sameColumn2 FROM Cities
ORDER BY sameColumn1,sameColumn2
select CONCAT(Name, '(',substr(occupation, 1, 1), ')') AS f1
from OCCUPATIONS
union
select temp.str AS f1 from
(select count(occupation) AS counts, occupation, concat('There are a total of ' ,count(occupation) ,' ', lower(occupation),'s.') As str from OCCUPATIONS group by occupation order by counts ASC, occupation ASC
) As temp
order by f1
My database table has 15 records and I want to show 9 at random on screen.
SELECT * FROM tablename ORDER BY RAND() LIMIT 9
This works as expected, but what if the table only has 9 records? I need to pull 15 random records.
I understand this will duplicate one or more records, but that's my intention.
Your select will only pull the number of records in the table regardless of the order by. You can use various means to duplicate the table data, however, before you order them. For example, union all of the rows together twice:
select * from
(
select * from tablename
union all
select * from tablename
) as tmp
order by rand() limit 9
RAND() itself is not efficient when you deal with a large database.
A better way of doing such query is to:
-1. Query the largest id (assume id is the unique key)
-2. use javascript of php function to generate 15 random numbers from 1 to max_id, push to -array
-3. Implode the array (e.g. $id_list = "'".implode("', '", $id_list)."'")
-4. Select * from tablename where id in ($id_list)
This will work even if you have only 1 row in the table. If you have less than 15 (say 11) rows, you'll have all 11 in the result plus 4 more random ones:
SELECT col1, col2, ..., colN -- the columns of `tablename` only
FROM
( SELECT a.i, b.j, t.*
FROM
( SELECT *, RAND() AS rnd
FROM tablename
ORDER BY rnd LIMIT 15
) AS t
CROSS JOIN
( SELECT 1 AS i UNION ALL SELECT 2 UNION ALL
SELECT 3 UNION ALL SELECT 4 )
AS a
CROSS JOIN
( SELECT 1 AS j UNION ALL SELECT 2 UNION ALL
SELECT 3 UNION ALL SELECT 4 )
AS b
ORDER BY i, j, rnd
LIMIT 15
) AS t15
ORDER BY RAND() ;
If you want "more" randomness, having duplicate or triplicate rows in the results with possibly some rows not shown at all, replace the last five lines with:
AS b
ORDER BY RAND()
LIMIT 15
) AS t15 ;
How can I get the n-th row of a TSQL query results?
Let's say, I want to get the 2nd row of this SELECT:
SELECT * FROM table
ORDER BY 2 ASC
What version of SQL Server are you targeting? If 2005 or greater, you can use ROW_NUMBER to generate a row number and select using that number. http://msdn.microsoft.com/en-us/library/ms186734.aspx
WITH orderedtable AS
(
SELECT *, ROW_NUMBER() OVER (ORDER BY <your order here>) AS 'RowNumber'
FROM table
)
SELECT *
FROM orderedtable
WHERE RowNumber = 2;
You can use a trick combining TOP with ORDER BY ASC/DESC to achieve an effect similar to MySQL's LIMIT:
SELECT TOP 2 * INTO #temptable FROM table
ORDER BY 2 ASC
SELECT TOP 1 * FROM #temptable
ORDER BY 2 DESC
or without temptable, but nested statements:
SELECT TOP 1 * FROM
(
SELECT TOP 2 * FROM table
ORDER BY 2 ASC
) sub
ORDER BY 2 DESC
The first time you select all rows up to the one you want to actually have, and in the second query you select only the first of the remaining when ordering them reversely, which is exactly the one you want.
Source: http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=850&lngWId=5
One way;
;with T(rownumber, col1, colN) as (
select
row_number() over (order by ACOLUMN) as rownumber,
col1,
colN
from
atable
)
select * from T where rownumber = 2