I vaguely remember there being a function that does this, but I think I may be going crazy.
Say I have a datatable, call it table1. It has three columns: column1, column2, column3. The query
SELECT * FROM table1
returns all rows/columns from table1. Isn't there some type of EXPAND function that allows me to duplicate that result? For example, if I want to duplicate everything from the SELECT * FROM table1 query three times, I can do something like EXPAND(3) ?
In BigQuery, I would recommend a CROSS JOIN:
SELECT t1.*
FROM table1 CROSS JOIN
(SELECT 1 as n UNION ALL SELECT 2 UNION ALL SELECT 3) n;
This can get cumbersome for lots of copies, but you can simplify this by generating the numbers:
SELECT t1.*
FROM table1 CROSS JOIN
UNNEST(GENERATE_ARRAY(1, 3)) n
This creates an array with three elements and unnests it into rows.
In both these cases, you can include n in the SELECT to distinguish the copies.
Below is for BigQuery Standard SQL
I think below is close enough to what "got you crazy" o)
#standardSQL
SELECT copy.*
FROM `project.dataset.tabel1` t, UNNEST(FN.EXPAND(t, 3)) copy
To be able to do so, you can leverage recently announced support for persistent standard SQL UDFs, namely - you need to create FN.EXPAND() function as in below example (note: you need to have FN dataset in your project - or use existing dataset in which case you should use YOUR_DATASET.EXPAND() reference
#standardSQL
CREATE FUNCTION FN.EXPAND(s ANY TYPE, dups INT64) AS (
ARRAY (
SELECT s FROM UNNEST(GENERATE_ARRAY(1, dups))
)
);
Finally, if you don't want to create persistent UDF - you can use temp UDF as in below example
#standardSQL
CREATE TEMP FUNCTION EXPAND(s ANY TYPE, dups INT64) AS ( ARRAY(
SELECT s FROM UNNEST(GENERATE_ARRAY(1, dups))
));
SELECT copy.*
FROM `project.dataset.tabel1` t, UNNEST(EXPAND(t, 3)) copy
if you want a cartesian product (all the combination on a row ) you could use
SELECT a.*, b.*, c.*
FROM table1 a
CROSS JOIN table1 b
CROSS JOIN table1 c
if you want the same rows repeated you can use UNION ALL
SELECT *
FROM table1
UNION ALL
SELECT *
FROM table1
UNION ALL
SELECT *
FROM table1
Use union all
Select * from table1
Union all
Select * from table1
Union all
Select * from table1
Union all
Select * from table1
For reuse purposes can embed this code in a procedure like
Create Procedure
expandTable(tablename
varchar2(50))
As
Select * from table1
Union all
Select * from table1
Union all
Select * from table1
Union all
Select * from table1
End
/
Related
This code does precisely what I want: finds the difference between two tables, including nulls, and returns them. Thanks to: sql query to return differences between two tables
(
SELECT * FROM table1
EXCEPT
SELECT * FROM table2
)
UNION ALL
(
SELECT * FROM table2
EXCEPT
SELECT * FROM table1
)
I am having trouble getting this to turn into a temporary table (or even a regular table) to store its results for later use. Is there a way that I can tack on INSERT INTO here or generate a temp table from this beautiful query?
Select from your existing query as a sub-query INTO the temp table of your choice.
SELECT *
INTO #temp1
FROM (
(
SELECT * FROM #table1
EXCEPT
SELECT * FROM #table2
)
UNION ALL
(
SELECT * FROM #table2
EXCEPT
SELECT * FROM #table1
)
) X
I was recently asked this question and was a little stumped so I want to ask the experts...
Given two tables A & B, I want to return all the values from A and B that do not overlap. Think of two overlapping circles; how do we return all the data that is NOT in the overlapping center section? And, I had to use ANSI Standard SQL rather than Oracle syntax.
Assuming we want everything exclusive to both A & B, my answer was
select *
from A
cross join B
minus
(select a.common_column from a
intersect
select b.common_column)
Does this look correct, or even close? If it is correct, is there a more efficient way to do this?
BTW - my solution was soundly rejected....
Thank you!
Given the tables A and B, you are looking for (A U B) - (A & B). In other words, you need A union B minus their intersection. Remember A and B must be union-compatible for this query to work. I would do:
(select * from A
union
select * from B
)
minus
(select * from A
intersect
select * from B
)
May be full outer join?
select coalesce(A.col, B.col)
from A full outer join B on A.col = B.col
where A.col is null or B.col is null;
For computing a set symmetric difference, you can use a combination of MINUS and UNION ALL:
select * from (
(select * from A
minus
select * from B)
union all
(select * from B
minus
select * from A)
)
Your query was rejected because it is syntactically incorrect: the number of columns differ and it confuses cross join and union all. However, I think you have the right idea for solving this.
You can easily fix this:
(select *
from A
union all
select *
from B
) minus
(select *
from A
intersect
select *
from B
);
That is, combine everything using union all and then subtract the rows that occur in both tables.
Of course, if there is a single id, then you can use the id with join and other operations.
Just like Frank Schmitt answered in the meantime:
Here it is including a data example:
WITH
table_a(name) AS (
SELECT 'From_A_1'
UNION ALL SELECT 'From_A_2'
UNION ALL SELECT 'From_A_3'
UNION ALL SELECT 'From_A_4'
UNION ALL SELECT 'From_A_5'
UNION ALL SELECT 'From_BOTH_6'
UNION ALL SELECT 'From_BOTH_7'
UNION ALL SELECT 'From_BOTH_8'
)
,
table_b(name) AS (
SELECT 'From_B_1'
UNION ALL SELECT 'From_B_2'
UNION ALL SELECT 'From_B_3'
UNION ALL SELECT 'From_B_4'
UNION ALL SELECT 'From_B_5'
UNION ALL SELECT 'From_BOTH_6'
UNION ALL SELECT 'From_BOTH_7'
UNION ALL SELECT 'From_BOTH_8'
)
(SELECT * FROM table_a EXCEPT SELECT * FROM table_b)
UNION ALL
(SELECT * FROM table_b EXCEPT SELECT * FROM table_a)
ORDER BY name
;
name
From_A_1
From_A_2
From_A_3
From_A_4
From_A_5
From_B_1
From_B_2
From_B_3
From_B_4
From_B_5
You will need to select all the data from both tables, except where they overlap, and then combine the data with a union. The code provided should work for your example.
SELECT *
FROM
(
SELECT * FROM Table1
EXCEPT SELECT * FROM Table2
)
UNION
SELECT *
FROM
(
SELECT * FROM Table2
EXCEPT SELECT * FROM Table1
)
Hope this helps.
I need to return the unique records between two tables. Ideally, an UNION would solve my problem but both tables contain an object field which gives me an error(cannot ORDER objects without MAP or ORDER method) when I do UNION/distinct.
So, I was wondering if I can do a UNION ALL(to avoid the error) to get all the records first then do something to return only the unique records from there. I tried analytic function combined with the UNION ALL query but no luck so far.
Select * from Table1
union all
Select * from table2
Any help? Note:I need to return all fields.
I actually solved the problem using analytic function+row_num. The query will choose the first record for each set of duplicates hence returning only the unique records.
select * from
(
select ua.*,row_number() over (partition by p_id order by p_id ) row_num from
(
select * from table1
union all
select * from table2
)ua
) inner
where inner.row_num=1
How about this :
SELECT DISTINCT A.* FROM
(
Select * from Table1
union all
Select * from table2
) A;
(or)
SELECT col1,col2,col3...coln FROM
(
Select col1,col2,col3...coln from Table1
union all
Select col1,col2,col3...coln from table2
) A
GROUP BY A.col1,col2,col3...coln;
UNION ALL will give duplicate values as well .. instead use UNION and see if you are facing the error
I need to count rows in more than one table in SQL Server 2008. I do this:
select count(*) from (select * from tbl1 union all select * from tbl2)
But it gives me an error of incorrect syntax near ). Why?
PS. The actual number of tables can be more than 2.
In case you have different number of columns in your tables try this way
SELECT count(*)
FROM (
SELECT NULL as columnName
FROM tbl1
UNION ALL
SELECT NULL
FROM tbl2
) T
try this:
You have to give a name to your derived table
select count(*) from
(select * from tbl1 union all select * from tbl2)a
I think you have to alias the SELECT in the FROM clause:
select count(*)
from
(
select * from tbl1
union all
select * from tbl2
) AS SUB
You also need to ensure that the * in both tables tbl1 and tbl2 return exactly the same number of columns and they have to be matched in their type.
I don't like doing the union before doing the count. It gives the SQL optimizer an opportunithy to choose to do more work.
AlexK's (deleted) solution is fine. You could also do:
select (select count(*) from tbl1) + (select count(*) from tbl2) as cnt
Question: I have an SQL function which returns a list of files
now I should join an additional list to that list with an union, but only if the user is admin.
Is that possible? Something like:
CREATE FUNCTION tfu_CMS_Process(#bIsAdmin bit )
-- Add the parameters for the function here
RETURNS TABLE
AS
RETURN
(
SELECT * FROM TABLE1
if bIsAdmin
UNION ALL
SELECT * FROM TABLE2
end if
)
SELECT *
FROM table1
UNION ALL
SELECT *
FROM table2
WHERE #isAdmin = 1