I have two tables with articles.
table 1 article and table 2 articlefm
both tables have one field with artnr.
'table 1' has 2192 artnr and 'table 2' has 2195 artnr.
I want in my query to find out whats the artnr of the 3 articles that is not matched.
If 'table 2' has more articles then 'table 1' then I need a list with those artnr.
How can I make this?
You can do this using a FULL JOIN:
SELECT COALESCE(t1.Artnr, t2.Artnr) AS Artnr,
CASE WHEN t1.Artnr IS NULL THEN 'Table1' ELSE 'Table2' END AS MissingFrom
FROM Table1 AS t1
FULL JOIN Table2 AS t2
ON t1.Artnr = t2.Artnr
WHERE t1.Artnr IS NULL
OR t2.Artnr IS NULL;
Note, that just because there is a difference in the count of 3, it does not necessarily mean that there are only 3 records in one table missing from the other. Imagine the following:
Table1 Table2
------ -------
1 2
2 4
3 6
4
The difference in count is 1, but there are actually 2 records present in table1 that aren't in table2, and 1 in table2 that isn't in table1. Using the above full join method you would get a result like:
Artnr | MissingFrom
------+-------------
1 | Table1
3 | Table1
6 | Table2
In most databases you can use except (SQL standard) or minus (Oracle specific):
select artnr
from articlefm -- table 2
except
select artnr
from article -- table 1
Else you could try a not in:
select atrnr
from articlefm -- table 2
where atrnr not in
( select artnr
from article -- table 1
)
This will give you the article numbers that exist in 2, but not in 1.
Related
I am new to sql and are trying to combine a column value from three different tables and combine to one row in DB2 Warehouse on Cloud. Each table consists of only one row and unique column name. So what I want to is just join these three to one row their original column names.
Each table is built from a statement that looks like this:
SELECT SUM(FUEL_TEMP.FUEL_MLAD_VALUE) AS FUEL
FROM
(SELECT ML_ANOMALY_DETECTION.MLAD_METRIC AS MLAD_METRIC, ML_ANOMALY_DETECTION.MLAD_VALUE AS FUEL_MLAD_VALUE, ML_ANOMALY_DETECTION.TAG_NAME AS TAG_NAME, ML_ANOMALY_DETECTION.DATETIME AS DATETIME, DATA_CONFIG.SYSTEM_NAME AS SYSTEM_NAME
FROM ML_ANOMALY_DETECTION
INNER JOIN DATA_CONFIG ON
(ML_ANOMALY_DETECTION.TAG_NAME =DATA_CONFIG.TAG_NAME AND
DATA_CONFIG.SYSTEM_NAME = 'FUEL')
WHERE ML_ANOMALY_DETECTION.MLAD_METRIC = 'IFOREST_SCORE'
AND ML_ANOMALY_DETECTION.DATETIME >= (CURRENT DATE - 9 DAYS)
ORDER BY DATETIME DESC)
AS FUEL_TEMP
I have tried JOIN, INNER JOIN, UNION/UNION ALL, but can't get it to work as it should. How can I do this?
Use a cross-join like this:
create table table1 (field1 char(10));
create table table2 (field2 char(10));
create table table3 (field3 char(10));
insert into table1 values('value1');
insert into table2 values('value2');
insert into table3 values('value3');
select *
from table1
cross join table2
cross join table3;
Result:
field1 field2 field3
---------- ---------- ----------
value1 value2 value3
A cross join joins all the rows on the left with all the rows on the right. You will end up with a product of rows (table1 rows x table2 rows x table3 rows). Since each table only has one row, you will get (1 x 1 x 1) = 1 row.
Using UNION should solve your problem. Something like this:
SELECT
WarehouseDB1.WarehouseID AS TheID,
'A' AS TheSystem,
WarehouseDB1.TheValue AS TheValue
FROM WarehouseDB1
UNION
SELECT
WarehouseDB2.WarehouseID AS TheID,
'B' AS TheSystem,
WarehouseDB2.TheValue AS TheValue
FROM WarehouseDB2
UNION
WarehouseDB3.WarehouseID AS TheID,
'C' AS TheSystem,
WarehouseDB3.TheValue AS TheValue
FROM WarehouseDB3
Ill adapt the code with your table names and rows if you tell me what they are. This kind of query would return something like the following:
TheID TheSystem TheValue
1 A 10
2 A 20
3 B 30
4 C 40
5 C 50
As long as your column names match in each query, you should get the desired results.
I am trying to solve a problem. It seems that of a brain teaser if you ask me.
Given two tables, return only values from the first table when there is a match for EVERY record in a second table. So a record in table 1 must have a match to every record in table 2. If table 2 has fewer than every row I want to exclude it from the final result.
This must be done without using count, having, group by. I must solve it with union, intersect, except, exists.
I am using SQL Server BTW.
CREATE TABLE table1 (id int, lid int)
INSERT INTO table1 VALUES (1, 1),(1, 2),(1,3),(1,4),(2,1),(3,3),(4,4)
CREATE TABLE table2 (lid int)
INSERT INTO table2 VALUES (1),(2),(3),(4)
Table 1:
id lid
--------
1 1
1 2
1 3
1 4
2 1
3 3
4 4
Table2:
lid
-----
1
2
3
4
This method here is "not the way I am supposed to solve it". Frustrating because this solution is so simple and does exactly what it should do. I can't use count, group by, and having.
SELECT id
FROM dbo.table1, dbo.table2
WHERE table1.lid = table2.lid
GROUP BY id
HAVING COUNT(*) = (SELECT COUNT(*) FROM dbo.table2)
So basically I need to find a way to exclude the results from the first table when there is not a full set of matches in table 2. In this example the only value in table 1 with a match to every record in table 2 is 1. 2,3,4 would need to be excluded.
What you're looking for has a name. It's called relational division. It has no equivalent in SQL, although it can be emulated in a variety of ways. Joe Celko has written one of the most complete blog posts about the topic.
Since you must use some of the more basic relational operators in SQL, this could be one solution for you:
SELECT DISTINCT id
FROM table1 t1a
WHERE NOT EXISTS (
SELECT *
FROM table2
WHERE NOT EXISTS (
SELECT *
FROM table1 t1b
WHERE t1a.id = t1b.id
AND t2.lid = t1b.lid
)
)
It reads in English, informally:
Get me all the elements in table1 for which there is no element in table2, which doesn't match such an element from table1
Or also:
Get me the elements from table1, which match all the elements in table2
That's one of the solutions:
select distinct id from table1 AS T1
where not exists(
select lid from table2
except
select lid from table1 where id = T1.id
)
I have the following two tables with data like so:
Table Values
var_label
1
2
2
1
3
Table Codes
var_code
1
2
4
2
I need to join these tables and get the distinct result. The var_label and var_code are equal pieces of data. I want to have the joined output like so:
MyColumn
1
2
3
4
Wht's the best way to do this?
Use UNION without ALL(implicit distinct) like so:
SELECT var_label AS MyColumn
FROM Values
UNION
SELECT var_code
FROM Codes
Live Demo
SELECT var_label
FROM Table1 as MyColumn
UNION
SELECT var_data as MyColumn
FROM Table2
you can give aliases for getting only one colum name.
SQLFiddle DEMO
SELECT distinct(var_label)
FROM Table1
UNION
SELECT distinct(var_data)
FROM Table2
I'm a bit confused on this. I have a data table structured like this:
Table: Data
DataID Val
1 Value 1
2 Value 2
3 Value 3
4 Value 4
Then I have another table structured like this:
Table: Table1
Col1 Col2
1 2
3 4
4 3
2 1
Both columns from Table1 point to the data in the data table. How can I get this data to show in a query? For example, a query to return this:
Query: Query1
Column1 Column2
Value 1 Value 2
Value 3 Value 4
Value 4 Value 3
Value 2 Value 1
I'm familiar enough with SQL to do a join with one column, but lost beyond that. Any help is appreciated. Sample sql or a link to something to read. Thanks!
PS: This is in sqlite
You can join the same table twice:
Select
d1.val As column1,
d2.val As column2
From table1 t
Join data d1 On ( d1.dataId = t.col1 )
Join data d2 On ( d2.dataId = t.col2 )
Setup:
create table main(id integer unsigned);
create table test1(id integer unsigned);
create table test2(id integer unsigned);
insert into main(id) value(1);
insert into test1(id) value(1);
insert into test1(id) value(1);
insert into test2(id) value(1);
insert into test2(id) value(1);
insert into test2(id) value(1);
Using:
select main.id,
count(test1.id),
count(test2.id)
from main
left join test1 on main.id=test1.id
left join test2 on main.id=test2.id
group by main.id;
...returns:
+------+-----------------+-----------------+
| id | count(test1.id) | count(test2.id) |
+------+-----------------+-----------------+
| 1 | 6 | 6 |
+------+-----------------+-----------------+
How to get the desired result of 1 2 3?
EDIT
The solution should be extensible,I'm going to query multiple count() information about main.id in the future.
Not optimal, but works:
select
count(*),
(select count(*) from test1 where test1.id = main.id) as test1_count,
(select count(*) from test2 where test2.id = main.id) as test2_count
from main
You created tables that contain the following:
Table main
id
----
1
Table test1
id
----
1
1
Table test2
id
----
1
1
1
When you join this like you do you will get the following
id id id
-----------
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
So how should SQL answer differently?
You can call:
SELECT id,COUNT(id) FROM main GROUP BY id
for every table, then join them by id.
Not sure if this works in MySQL exactly as written (I'm using Oracle):
1 select main.id, t1.rowcount, t2.rowcount
2 from main
3 left join (select id,count(*) rowcount from test1 group by id) t1
4 on t1.id = main.id
5 left join (select id,count(*) rowcount from test2 group by id) t2
6* on t2.id = main.id
SQL> /
ID ROWCOUNT ROWCOUNT
1 2 3
You're inadvertently creating a Cartesian product between test1 and test2, so every matching row in test1 is combined with every matching row in test2. The result of both counts, therefore, is the count of matching rows in test1 multiplied by the count of matching rows in test2.
This is a common SQL antipattern. A lot of people have this problem, because they think they have to get both counts in a single query.
Some other folks on this thread have suggested ways of compensating for the Cartesian product through creative use of subqueries, but the solution is simply to run two separate queries:
select main.id, count(test1.id)
from main
left join test1 on main.id=test1.id
group by main.id;
select main.id, count(test2.id)
from main
left join test2 on main.id=test2.id
group by main.id;
You don't have to do every task in a single SQL query! Frequently it's easier to code -- and easier for the RDBMS to execute -- multiple simpler queries.
You can get the desired result by using:
SELECT COUNT(*) as main_count,
(SELECT COUNT(*) FROM table1) as table1Count,
(SELECT COUNT(*) from table2) as table2Count FROM main