If you are on SQL Server 2017 or Azure, see Mathieu Renda answer.
I had a similar issue when I was trying to join two tables with one-to-many relationships. In SQL 2005 I found that XML PATH
method can handle the concatenation of the rows very easily.
If there is a table called STUDENTS
SubjectID StudentName
---------- -------------
1 Mary
1 John
1 Sam
2 Alaina
2 Edward
Result I expected was:
SubjectID StudentName
---------- -------------
1 Mary, John, Sam
2 Alaina, Edward
I used the following T-SQL
:
SELECT Main.SubjectID,
LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
(
SELECT DISTINCT ST2.SubjectID,
(
SELECT ST1.StudentName + ',' AS [text()]
FROM dbo.Students ST1
WHERE ST1.SubjectID = ST2.SubjectID
ORDER BY ST1.SubjectID
FOR XML PATH ('')
) [Students]
FROM dbo.Students ST2
) [Main]
You can do the same thing in a more compact way if you can concat the commas at the beginning and use substring
to skip the first one so you don't need to do a sub-query:
SELECT DISTINCT ST2.SubjectID,
SUBSTRING(
(
SELECT ','+ST1.StudentName AS [text()]
FROM dbo.Students ST1
WHERE ST1.SubjectID = ST2.SubjectID
ORDER BY ST1.SubjectID
FOR XML PATH ('')
), 2, 1000) [Students]
FROM dbo.Students ST2
SELECT owner, table_name
FROM dba_tables
This is assuming that you have access to the DBA_TABLES
data dictionary view. If you do not have those privileges but need them, you can request that the DBA explicitly grants you privileges on that table, or, that the DBA grants you the SELECT ANY DICTIONARY
privilege or the SELECT_CATALOG_ROLE
role (either of which would allow you to query any data dictionary table). Of course, you may want to exclude certain schemas like SYS
and SYSTEM
which have large numbers of Oracle tables that you probably don't care about.
Alternatively, if you do not have access to DBA_TABLES
, you can see all the tables that your account has access to through the ALL_TABLES
view:
SELECT owner, table_name
FROM all_tables
Although, that may be a subset of the tables available in the database (ALL_TABLES
shows you the information for all the tables that your user has been granted access to).
If you are only concerned with the tables that you own, not those that you have access to, you could use USER_TABLES
:
SELECT table_name
FROM user_tables
Since USER_TABLES
only has information about the tables that you own, it does not have an OWNER
column – the owner, by definition, is you.
Oracle also has a number of legacy data dictionary views-- TAB
, DICT
, TABS
, and CAT
for example-- that could be used. In general, I would not suggest using these legacy views unless you absolutely need to backport your scripts to Oracle 6. Oracle has not changed these views in a long time so they often have problems with newer types of objects. For example, the TAB
and CAT
views both show information about tables that are in the user's recycle bin while the [DBA|ALL|USER]_TABLES
views all filter those out. CAT
also shows information about materialized view logs with a TABLE_TYPE
of "TABLE" which is unlikely to be what you really want. DICT
combines tables and synonyms and doesn't tell you who owns the object.
Best Answer
A subquery in your statement is wrong. You left off either a
WHERE
orFIRST
clause, and now it's returning multiple values when it shouldn't.You're basically trying to say
PREVIOUS_DAY_CLOSE
should be multiple values at the same time. I'm guessing you left off aWHERE
clause on your subselect, which would link the results of that subquery to the particular row you're trying to update. Something like (note the bolded line):Although, I'll be honest, I'm not exactly sure what you're trying to do with this query.