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Combine two tables for one output
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Closed 8 years ago.
I have two tables now I need a select or join command in SQL to have the third table just like image below
My two tables are like this:
I only know a simple things about join command in SQL, should I use join or something else?
I do not want have the third table in my database, I want that for a short time (something like virtual table). Please help !
You are actually looking for UNION or UNION ALL.
First of all, there is no condition on which to JOIN tables (review your documentation on JOIN) and JOIN is used for retrieving information about one logical element, let's say Event in your case, which has details stored in more tables.
Secondly, JOIN will make one result set with all of the columns of your two tables, when actually you are not trying to get all columns, but all rows.
For this you will have to use UNION or UNION ALL like this:
SELECT
EventID,
ID,
EventName,
Date,
Pic,
Privacy
FROM Table1
UNION ALL
SELECT
PLID AS EventID,
ID AS ID,
PlaceName AS EventName,
Date AS Date,
NULL AS Pic,
NULL AS Privacy
FROM Table2
In order to sort the result you get from the result set returned by the queries above you will need to wrap your above SELECT statements with another SELECT and use a WHERE clause at that level, like below:
SELECT *
FROM (SELECT
EventID,
ID,
EventName,
Date,
Pic,
Privacy
FROM Table1
UNION ALL
SELECT
PLID AS EventID,
ID AS ID,
PlaceName AS EventName,
Date AS Date,
NULL AS Pic,
NULL AS Privacy
FROM Table2) AS Result
WHERE Date > '2014-05-26'
What you're looking to do is a UNION or UNION ALL, not a join. See: http://www.w3schools.com/sql/sql_union.asp
UNION combines two tables without connecting their content. Your example shows all 4 records from the original tables unmodified.
A JOIN solution links the two tables. It's very common and you will probably use it if you're building a relational database, but it won't give you the example result.
Since the two tables don't have identical # of columns, you have to help it out here:
SELECT EventID, EventName, Date, Pic, privacy FROM [table 1]
UNION ALL
SELECT PLID, PlaceName, Date, null, null FROM [table 2]
You want to have one table from two different tables. So you need unified result set from each by renaming column in SELECT statement:
SELECT `EventID` AS `ObjectID`, `EventName` AS `ObjectName`, .... FROM table_1 ...
similary with table_2
Then combine to one result set:
SELECT `ID` AS `ObjectID`, `EventName` AS `ObjectName`, .... FROM table_1 ...
UNION
SELECT `PlaceID` AS `ObjectID`, `PlaceName` AS `ObjectName`, .... FROM table_2 ...
My mistake, I didn't take the time to examine the pictures fully. you would have to use Union since you want to return what is in both tables.
Related
I am using Sybase for my SQL coding.
I was comparing tables which have the same columns such as follows:
SELECT name, date, time, location
FROM
(SELECT * FROM table1
UNION ALL
SELECT * FROM table2) data
GROUP BY name, date, time, location
HAVING count(*)!=2
Now, I want to be able to compare the table1 and table2 but now table2 has another column called origin and I am not sure on how to extend my current logic to make it happen.
---Intention: to be able to compare the two tables with varying column numbers
---How to modify this code to do it?
I want to be able to show the differences between the two tables after the query.
May someone guide me? I dont want to use joins or minus, I prefer to use the UNION way.
If you want to union two different tables, you must make up missing columns. E.g.:
SELECT name, date, time, location, origin FROM table2
UNION ALL
SELECT name, date, time, location, null as origin FROM table1
I think the problem is that you actually want to ignore the extra column. The problem with using select * is that things can change.
SELECT name, date, time, location
FROM (
SELECT name, date, time, location FROM table1
UNION ALL
SELECT name, date, time, location FROM table2
) data
GROUP BY name, date, time, location
HAVING count(*) != 2
If you're not going to use select * in one half of the union there isn't any reason include origin in the first place.
Is there a way to apply a single query across the concatenated rows of multiple tables? I have several tables storing metrics data, where data is initially collected in 10 second intervals, but is periodically rolled up into 1 minute intervals in another table and ultimately into 10 minute intervals in a third table.
That is, I want to be able to do something like:
SELECT value FROM table1 + table2 + table3
WHERE age(current_timestamp, time) > '2 days'
AND metrics_name = 'foo';
I don't think a JOIN operation is the right solution here. It looks like I can get the result I want using the UNION operator, which would look something like:
SELECT value from TABLE1 ...
UNION SELECT value FROM table2 ...
UNION SELECT value from TABLE3 ...
Where ... is the contents of my WHERE clause (etc), but this gets messy very quickly if the individual SELECT queries are complicated (and fails the "don't repeat yourself" mantra). Is there a different way of cracking this particular nut?
Use a nested query with the UNION in the nested quer. And I highly recommend you use UNION ALL unless you want to eliminate duplicates, which you won't in this case, so use UNION ALL.
SELECT
value
FROM (
SELECT value, age, metrics_name FROM Table1
UNION ALL SELECT value age, metrics_name FROM Table2
UNION ALL SELECT value age, metrics_name FROM Table3
) AS All_Metrics
WHERE
All_Metrics.age(current_timestamp, time) > '2 days'
AND All_Metrics.metrics_name = 'foo';
Hypothetically I want to merge 2 tables from different databases into one table, which includes all the data from the 2 tables:
The result would look like something like this:
Aren't the entries in the result table redundant, because there are 2 entries with Porsche and VW? Or can I just add the values in the column 'stock' because the column 'Mark' is explicit?
you need to create database link to another database here is the example on how to create database link http://psoug.org/definition/create_database_link.htm
after creating your select statement from another database should look: select * from tableA#"database_link_name"
Then you need to use MERGE statement to push data from another database so the merge statement should look something like this.
you can read about merge statement here: https://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_9016.htm#SQLRF01606
merge into result_table res
using (select mark, stock, some_unique_id
from result_table res2
union all
select mark, stock, some_unique_id
from tableA#"database_link_name") diff
on (res.some_unique_id = diff.some_unique_id )
when matched then
update set res.mark = diff.mark,
res.stock = diff.stock
when not matched then
insert
(res.mark,
res.stock,
res.some_unique_id)
values
(diff.mark,
diff.stock,
diff.some_unique_id);
I hope this will help you
SELECT ROW_NUMBER() OVER (ORDER BY Mark) AS new_ID, Mark, SUM(Stock) AS Stock
FROM
(
SELECT Mark,Stock FROM Database1.dbo.table1
UNION ALL
SELECT Mark,Stock FROM Database2.dbo.table2
) RESULT
GROUP BY Mark
Try this:
Select Mark, Stock, row_number() over(order by Mark desc) from table1
union all
Select Mark, Stock, row_number() over(order by Mark desc) from table2
regardless of the data redundancy, you could use union all clause to achieve this. Like:
Select * From tableA
UNION ALL
Select * From tanleB
Make sure the total number of columns and datatype should be matched between each
Don't forget to use fully qualified table names as the tables are in different databases
SELECT
Mark
,Stock
FROM Database1.dbo.table1
UNION ALL
SELECT
Mark
,Stock
FROM Database2.dbo.table2
If these are 2 live databases and you would need to constantly include rows from the 2 databases into your new database consider writing the table in your 3rd database as a view rather.
This way you can also add a column specifying which system the datarow is coming from. Summing the values is an option, however if you ever have a query regarding a incorrect summed value how would you know which system is the culprit?
Let's imagine that we have these 2 tables:
Table 1, with the column:
Field1
1
3
Table 2, with the column:
Field1
2
4
(Well they could also be called in any other way, but I want to represent that the type of table1.field1 is the same as table2.field1).
Would it be possible to do a SQL query that would return the following?
[1,2,3,4], I mean the numbers ordered by any criteria I would want but that criteria aplying to both tables. As far as I know ORDER BY can just ORDER by the values of a column, not by a general criteria like "from lower to higher number. And even if it could I believe the SELECT instruction can't fuse columns. I mean I think the best I could achieve with that instruction would be to get something like [(1,2),(1,4),(3,2),(3,4)] and later work on it, but this can be painful with lots of results.
And the application needs fields to be on different tables, I cannot merge them.
Any idea about how to deal with this?
Thanks a lot for your help.
Edit:
Oh, it was much easier than what I thought, with that instruction is not something hard to achieve.
Thank you everyone.
This is what the UNION statement is for. It lets you combine two SELECT statements into the same resultset:
SELECT Field1
FROM Table1
UNION ALL
SELECT Field1
FROM Table2
ORDER BY 1
can you do union all
Like below:
Select field 1
from
(Select field 1 from Table 1
Union
select field 1 from table 2)
order by field 1
Use union or Union all based on your need to repeat elements in both the tables or not.
select * from
(
select field1 as field_value from table1
union
select field2 as field_value from table2
)
order by field_value asc
I want to check my database for records that I already have recorded before making a web service call.
Here is what I imagine the query to look like, I just can't seem to figure out the syntax.
SELECT *
FROM (1,2,3,4) as temp_table
WHERE temp_table.id
LEFT JOIN table ON id IS NULL
Is there a way to do this? What is a query like this called?
I want to pass in a list of id's to mysql and i want it to spit out the id's that are not already in the database?
Use:
SELECT x.id
FROM (SELECT #param_1 AS id
FROM DUAL
UNION ALL
SELECT #param_2
FROM DUAL
UNION ALL
SELECT #param_3
FROM DUAL
UNION ALL
SELECT #param_4
FROM DUAL) x
LEFT JOIN TABLE t ON t.id = x.id
WHERE x.id IS NULL
If you need to support a varying number of parameters, you can either use:
a temporary table to populate & join to
MySQL's Prepared Statements to dynamically construct the UNION ALL statement
To confirm I've understood correctly, you want to pass in a list of numbers and see which of those numbers isn't present in the existing table? In effect:
SELECT Item
FROM IDList I
LEFT JOIN TABLE T ON I.Item=T.ID
WHERE T.ID IS NULL
You look like you're OK with building this query on the fly, in which case you can do this with a numbers / tally table by changing the above into
SELECT Number
FROM (SELECT Number FROM Numbers WHERE Number IN (1,2,3,4)) I
LEFT JOIN TABLE T ON I.Number=T.ID
WHERE T.ID IS NULL
This is relatively prone to SQL Injection attacks though because of the way the query is being built. It'd be better if you could pass in '1,2,3,4' as a string and split it into sections to generate your numbers list to join against in a safer way - for an example of how to do that, see http://www.sqlteam.com/article/parsing-csv-values-into-multiple-rows
All of this presumes you've got a numbers / tally table in your database, but they're sufficiently useful in general that I'd strongly recommend you do.
SELECT * FROM table where id NOT IN (1,2,3,4)
I would probably just do:
SELECT id
FROM table
WHERE id IN (1,2,3,4);
And then process the list of results, removing any returned by the query from your list of "records to submit".
How about a nested query? This may work. If not, it may get you in the right direction.
SELECT * FROM table WHERE id NOT IN (
SELECT id FROM table WHERE 1
);