I'm having trouble with the 'Ambiguous column name' issue in Transact-SQL, using the Microsoft SQL 2012 Server Management Studio.
I´ve been looking through some of the answers already posted on Stackoverflow, but they don´t seem to work for me, and parts of it I simply don´t understand or loses the general view of.
Executing the following script :
USE CDD
SELECT Artist, Album_title, track_title, track_number, Release_Year, EAN_code
FROM Artists AS a INNER JOIN CD_Albumtitles AS c
ON a.artist_id = c.artist_id
INNER JOIN Track_lists AS t
ON c.title_id = t.title_id
WHERE track_title = 'bohemian rhapsody'
triggers the following error message :
Msg 209, Level 16, State 1, Line 3
Ambiguous column name 'EAN_code'.
Not that this is a CD database with artists names, album titles and track lists. Both the tables 'CD_Albumtitles' and 'Track_lists' have a column, with identical EAN codes. The EAN code is an important internationel code used to uniquely identify CD albums, which is why I would like to keep using it.
You need to put the alias in front of all the columns in your select list and your where clause. You're getting that error because one of the columns you have currently is coming from multiple tables in your join. If you alias the columns, it will essentially pick one or the other of the tables.
SELECT a.Artist,c.Album_title,t.track_title,t.track_number,c.Release_Year,t.EAN_code
FROM Artists AS a INNER JOIN CD_Albumtitles AS c
ON a.artist_id = c.artist_id
INNER JOIN Track_lists AS t
ON c.title_id = t.title_id
WHERE t.track_title = 'bohemian rhapsody'
so choose one of the source tables, prefixing the field with the alias (or table name)
SELECT Artist,Album_title,track_title,track_number,Release_Year,
c.EAN_code -- or t.EAN_code, which should retrieve the same value
By the way, try to prefix all the fields (in the select, the join, the group by, etc.), it's easier for maintenance.
Related
Good morning! I am currently working on creating a postgreSQL database with some client information, however I ran into an issue which I wasn't able to solve with my basic knowledge of SQL. Searching for this method also returned with no results which I found useful or applicable.
I have two tables: 'mskMobile' and 'emailData'. Both of those tables contain a column named 'email' and some of those emails overlap. I figured out that I can view those intersecting emails by requesting
SELECT "mailData".email
FROM "mailData"
JOIN "mskMobile"
ON "mailData".email="mskMobile".email;
Now I want to write the data of two other columns of those common rows in 'mskMobile' named 'name' and 'surname' to the corresponding columns in 'emailData' (named identically), however I cannot find any answer on how to do so. Any suggestions on how to execute this action?
UPDATE "mksMobile" SET name = "mailData".name, surname = "mailData".surname
FROM "mailData"
WHERE "mailData".email = "mskMobile".email;
After a bit more research I came up with a following way of declaring it:
SELECT "mailData".email, "mskMobile".num, "mskMobile".name
FROM "mailData"
INNER JOIN "mskMobile"
ON "mailData".email="mskMobile".email;
This allowed me to build a new table with the data combined.
This may be a case of my ignorance to what is meant by a dependency.
When I run the following query I get a slightly different list (more entries) to when I chose the menu option View Dependencies (first node level only) why would that be? I should add I am ignoring VIEW dependencies, for example I have a 2 foreign key relationships set up to 2 different tables (pretty much identical configuration) yet only 1 is shown in the View Dependencies yet both a seen in the following query.
I got this off some other post:
SELECT DISTINCT
pt.object_id PrimaryTableID, pt.name PrimaryTableName
FROM
REPDEV.sys.foreign_keys fk
JOIN
REPDEV.sys.tables ft ON fk.referenced_object_id = ft.object_id
JOIN
REPDEV.sys.tables pt ON fk.parent_object_id = pt.object_id
WHERE
ft.name = 'MyTable'
ORDER BY
2
Am I suppose to use other means to get table relationship dependencies?
Include full outer join instead of join (inner join) and add the clause
"fk.name is not null" in where.
Tell me if works :)
I have a mongo database and I'm trying to write an Eloquent code to change some fields before using them in WHERE or ORDER BY clauses. something like this SQL query:
Select ag.*, ht.*
from agency as ag inner join hotel as ht on ag.hotel_id = ht.id
Where ht.title = 'OrangeHotel'
-- or --
Select ag.*, ht.*
from agency as ag inner join hotel as ht on ag.hotel_id = ht.id
Order by ht.title
sometimes there is no other table and I just need to use calculated field in Where or Order By clause:
Select *
from agency
Where func(agency_admin) = 'testAdmin'
Select *
from agency
Order by func(agency_admin)
where func() is my custom function.
any suggestion?
and I have read Laravel 4/5, order by a foreign column for half of my problem, but I don't know how can I use it.
For the first query: mongodb only support "join" partially with the aggregation pipeline, which limits your aggregation in one collection. For "join"s between different collections/tables, just select from collections one by one, first the one containing the "where" field, then the one who should "join" with the former, and so on.
The second question just puzzled me for some minutes until I see this question and realized it's the same as your first question: sort the collection containing your sort field and retrive some data, then go to another.
For the 3rd question, this question should serve you well.
Using crystal reports version 14, MS sql server 2008
I am joining two tables and I need to filter in the join, so if a certain value exists in one of the table, I want to join to that record, if it does not exist, I want to have a null-record. I.e:
select * from sample left outer join test
on(sample.sample_number=test.sample_number and test.name='PREP')
I can run that in Sql server studio and get exactly what I want
What I can get in crystal reports is
select * from sample left outer join test
on(sample.sample_number=test.sample_number)
where test.name='PREP'
In the latter case, rows where test.name='PREP' does not exist will be removed and if there are samples that have no test.name='PREP', those samples will be removed.
Are there any ways I can do this in CR 14?
dummy tables:
Sample
sample_number,name
1,A
2,B
3,C
Test
sample_number,name
1,PREP
1,SOMETHING
2,SOMETHING
3,SOMETHING_ELSE
3,PREP
What I want:
1,A,1,PREP
2,B,NULL,NULL
3,C,3,PREP
(of course there are more fields in the tables and a selection of which fields, but this should illustrate what I want)
I know I can make views and query them directly in crystal, but if possible, I would avoid doing that.
Bah, found it:
Database expert - add table, select data source, add command. Then a custom sql can be added.
I have a table listing (gameid, playerid, team, max_minions) and I want to get the players within each team that have the lowest max_minions (within each team, within each game). I.e. I want a list (gameid, team, playerid_with_lowest_minions) for each game/team combination.
I tried this:
SELECT * FROM MinionView GROUP BY gameid, team
HAVING MIN(max_minions) = max_minions;
Unfortunately, this doesn't seem to work as it seems to select a random row from the available rows for each (gameid, team) and then does the HAVING comparison. If the randomly selected row doesn't match, it's simply skipped.
Using WHERE won't work either since you can't use aggregate functions within WHERE clauses.
LIMIT won't work since I have many more games and LIMIT limits the total number of rows returned.
Is there any way to do this without adding another table/view that contains (gameid, teamid, MIN(max_minions))?
Example data:
sqlite> SELECT * FROM MinionView;
gameid|playerid|team|champion|max_minions
21|49|100|Champ1|124
21|52|100|Champ2|18
21|53|100|Champ3|303
21|54|200|Champ4|356
21|57|200|Champ5|180
21|58|200|Champ6|21
64|49|100|Champ7|111
64|50|100|Champ8|208
64|53|100|Champ9|8
64|54|200|Champ0|226
64|55|200|ChampA|182
64|58|200|ChampB|15
...
Expected result (I mostly care about playerid, but included champion, max_minions here for better overview):
21|52|100|Champ2|18
21|58|200|Champ6|21
64|53|100|Champ9|8
64|58|200|ChampB|15
...
I'm using Sqlite3 under Python 3.1 if that matters.
This is in SQL Server, hopefully the syntax works for you too:
SELECT
MV.*
FROM
(
SELECT
team, gameid, min(max_minions) as maxmin
FROM
MinionView
GROUP BY
team, gameid
) groups
JOIN MinionView MV ON
MV.team = groups.team
AND MV.gameid = groups.gameid
AND MV.max_minions = groups.maxmin
In words, first you make the usual grouping query (the nested one). At this point you have the min value for each group but you don't know to which row it belongs. For this you join with the original table and match the "keys" (team, game and min) to get the other columns as well.
Note that if a team will have more than one member with the same value for max_minions then all these rows will be selected. If you only want one of them then that's probably a bit more complicated.