I have a table in Oracle where there are two columns. In the first column, sometimes there are duplicate values that corresspond to a different value in the second column. How can I write a query that shows only unique values of the first column and all possible values from the second column?
The table looks somewhat like below
COLUMN_1 | COLUMN_2
NUMBER_1 | 4
NUMBER_2 | 4
NUMBER_3 | 1
NUMBER_3 | 6
NUMBER_4 | 3
NUMBER_4 | 4
NUMBER_4 | 5
NUMBER_4 | 6
You can use listagg() if you are using Oracle 11G or higher like
SELECT
COLUMN_1,
LISTAGG(COLUMN_2, '|') WITHIN GROUP (ORDER BY COLUMN_2) "ListValues"
FROM table1
GROUP BY COLUMN_1
Else, see this link for an alternative for lower versions
Oracle equivalent of MySQL group_concat
i am new to cassandra and i am trying to read a row from database which contains values
siteId | country | someMap
1 | US | {a:b, x:z}
2 | PR | {a:b, x:z}
I have also created an index on table using create index on columnfamily(keys(someMap));
but still when i query as select * from table where siteId=1 and someMap contains key 'a'
it returns an entiremap as
1 | US | {a:b, x:z}
Can somebody help me on what should i do to get the value as
1 | US | {a:b}
You can not: even if internally each entry of a Map|List|Set is stored as a column you can only retrieve the whole collection but not part of it. You are not asking cassandra give me the entry of the map containing X, but the row whom map contains X.
HTH,
Carlo
I have a Hive table with the following fields:
id STRING , x STRING
where x can have values such as 'c'.
I need a query that display number of rows where column x contains a value 'c' and the number of rows where x has values are other than 'c'.
id | count(x='c') | count(x<>'c')
---|--------------|--------------
1 | 3 | 7
I don't know if it's possible.
You can try :
SELECT sum(if(x='c',1,0)), sum(if(x!='c',1,0)) FROM table_name;
This will print two columns. I didn't understand the id field in your sample output.
I want to identify all rows whose content in a clob column is not unique.
The query I use is:
select
id,
clobtext
from
table t
where
(select count(*) from table innerT where dbms_lob.compare(innerT.clobtext, t.clobtext) = 0)>1
However this query is very slow. Any suggestions to speed it up? I already tried to use the dbms_lob.getlength function to eliminate more elements in the subquery but I didn't really improve the performance (feels the same).
To make it more clear an example:
table
ID | clobtext
1 | a
2 | b
3 | c
4 | d
5 | a
6 | d
After running the query. I'd like to get (order doesn't matter):
1 | a
4 | d
5 | a
6 | d
In the past I've generated checksums (in my C# code) for each clob.
Whilst this will inccur a one off increase in io (to generate the checksum)
subsequent scans will be quicker, and you can index the value too
TK has a good PL\SQL example here:
Ask Tom
How can write a query for Oracle database such that I can find a comma delimited list of values from a column that contains comma delimited list of values. The :parameter passed to sql statement is also a comma delimited values that user selected.
For e.g
We have a column in tables that contains
1 | 'A','B','C'
2 | 'C','A'
3 | 'A','B'
on the web application interface we have multi select box that shows
A
B
C
and allows user to to select one or more items.
I want rows 1 and 2 to show up if they select A and B, If they select A only the all three should show up b/c all rows 1 to 3 have 'A' value in it.
This example will hopefully help and it matches the values irrespective of which order they appear in the string in the DB record.
Create example table:
CREATE TABLE t
(val VARCHAR2(100));
Insert records:
INSERT INTO t VALUES
('1|''A'',''B'',''C''');
INSERT INTO t VALUES
('2|''C'',''A''');
INSERT INTO t VALUES
('3|''A'',''B''');
Check values:
SELECT * FROM t;
1|'A','B','C'
2|'C','A'
3|'A','B'
Check solution for 'A':
SELECT val
FROM t
WHERE REGEXP_LIKE(val, '(A)');
1|'A','B','C'
2|'C','A'
3|'A','B'
Check solution for A and B
SELECT val
FROM t
WHERE REGEXP_LIKE(val, '(A|B).*(A|B)');
1|'A','B','C'
3|'A','B'
If you want to make sure the 1| part of the result isn't matched by anything then you could query using:
SELECT val
FROM t
WHERE REGEXP_LIKE(val, '(.\|.*)(A)');
and
SELECT val
FROM t
WHERE REGEXP_LIKE(val, '(.\|.*)(A|B).*(A|B)');
Hope this helps...
You could use a where clause with varying number of bind values, depending on the number of selected options:
TEST#PRJ> create table t (c varchar2(100));
TEST#PRJ> insert into t values ('2 | ''C'',''A''');
TEST#PRJ> insert into t values ('3 | ''A'',''B''');
TEST#PRJ> select * from t where c like '%''A''%' and c like '%''B''%';
C
----------------------------------------------------------------------------------------------------------------
1 | 'A','B','C'
3 | 'A','B'
TEST#PRJ> select * from t where c like '%''A''%';
C
----------------------------------------------------------------------------------------------------------------
1 | 'A','B','C'
2 | 'C','A'
3 | 'A','B'
If the values are stored in order you could use a single bind value:
TEST#PRJ> select * from t where c like '%''A''%''B''%';
C
-----------------------------------------------------------------------------------------
1 | 'A','B','C'
3 | 'A','B'