I have (and don't own, so I can't change) a table with a layout similar to this.
ID | CATEGORIES
---------------
1 | c1
2 | c2,c3
3 | c3,c2
4 | c3
5 | c4,c8,c5,c100
I need to return the rows that contain a specific category id. I starting by writing the queries with LIKE statements, because the values can be anywhere in the string
SELECT id FROM table WHERE categories LIKE '%c2%';
Would return rows 2 and 3
SELECT id FROM table WHERE categories LIKE '%c3%' and categories LIKE '%c2%'; Would again get me rows 2 and 3, but not row 4
SELECT id FROM table WHERE categories LIKE '%c3%' or categories LIKE '%c2%'; Would again get me rows 2, 3, and 4
I don't like all the LIKE statements. I've found FIND_IN_SET() in the Oracle documentation but it doesn't seem to work in 10g. I get the following error:
ORA-00904: "FIND_IN_SET": invalid identifier
00904. 00000 - "%s: invalid identifier"
when running this query: SELECT id FROM table WHERE FIND_IN_SET('c2', categories); (example from the docs) or this query: SELECT id FROM table WHERE FIND_IN_SET('c2', categories) <> 0; (example from Google)
I would expect it to return rows 2 and 3.
Is there a better way to write these queries instead of using a ton of LIKE statements?
You can, using LIKE. You don't want to match for partial values, so you'll have to include the commas in your search. That also means that you'll have to provide an extra comma to search for values at the beginning or end of your text:
select
*
from
YourTable
where
',' || CommaSeparatedValueColumn || ',' LIKE '%,SearchValue,%'
But this query will be slow, as will all queries using LIKE, especially with a leading wildcard.
And there's always a risk. If there are spaces around the values, or values can contain commas themselves in which case they are surrounded by quotes (like in csv files), this query won't work and you'll have to add even more logic, slowing down your query even more.
A better solution would be to add a child table for these categories. Or rather even a separate table for the catagories, and a table that cross links them to YourTable.
You can write a PIPELINED table function which return a 1 column table. Each row is a value from the comma separated string. Use something like this to pop a string from the list and put it as a row into the table:
PIPE ROW(ltrim(rtrim(substr(l_list, 1, l_idx - 1),' '),' '));
Usage:
SELECT * FROM MyTable
WHERE 'c2' IN TABLE(Util_Pkg.split_string(categories));
See more here: Oracle docs
Yes and No...
"Yes":
Normalize the data (strongly recommended) - i.e. split the categorie column so that you have each categorie in a separate... then you can just query it in a normal faschion...
"No":
As long as you keep this "pseudo-structure" there will be several issues (performance and others) and you will have to do something similar to:
SELECT * FROM MyTable WHERE categories LIKE 'c2,%' OR categories = 'c2' OR categories LIKE '%,c2,%' OR categories LIKE '%,c2'
IF you absolutely must you could define a function which is named FIND_IN_SET like the following:
CREATE OR REPLACE Function FIND_IN_SET
( vSET IN varchar2, vToFind IN VARCHAR2 )
RETURN number
IS
rRESULT number;
BEGIN
rRESULT := -1;
SELECT COUNT(*) INTO rRESULT FROM DUAL WHERE vSET LIKE ( vToFine || ',%' ) OR vSET = vToFind OR vSET LIKE ('%,' || vToFind || ',%') OR vSET LIKE ('%,' || vToFind);
RETURN rRESULT;
END;
You can then use that function like:
SELECT * FROM MyTable WHERE FIND_IN_SET (categories, 'c2' ) > 0;
For the sake of future searchers, don't forget the regular expression way:
with tbl as (
select 1 ID, 'c1' CATEGORIES from dual
union
select 2 ID, 'c2,c3' CATEGORIES from dual
union
select 3 ID, 'c3,c2' CATEGORIES from dual
union
select 4 ID, 'c3' CATEGORIES from dual
union
select 5 ID, 'c4,c8,c5,c100' CATEGORIES from dual
)
select *
from tbl
where regexp_like(CATEGORIES, '(^|\W)c3(\W|$)');
ID CATEGORIES
---------- -------------
2 c2,c3
3 c3,c2
4 c3
This matches on a word boundary, so even if the comma was followed by a space it would still work. If you want to be more strict and match only where a comma separates values, replace the '\W' with a comma. At any rate, read the regular expression as:
match a group of either the beginning of the line or a word boundary, followed by the target search value, followed by a group of either a word boundary or the end of the line.
As long as the comma-delimited list is 512 characters or less, you can also use a regular expression in this instance (Oracle's regular expression functions, e.g., REGEXP_LIKE(), are limited to 512 characters):
SELECT id, categories
FROM mytable
WHERE REGEXP_LIKE('c2', '^(' || REPLACE(categories, ',', '|') || ')$', 'i');
In the above I'm replacing the commas with the regular expression alternation operator |. If your list of delimited values is already |-delimited, so much the better.
How to loop Oracle query through the date? I have to put variable in 4 place. My query start with WITH AS, so I can't use Oracle SQL Loop through Date Range solution.
I also can't create temporary table.
Here is my attempt:
WITH d
AS (
SELECT DATE'2015-06-22' + LEVEL - 1 AS current_d
FROM dual
CONNECT BY DATE'2015-06-22' + LEVEL - 1 < DATE'2015-10-04'
),
OrderReserve
AS (
SELECT cvwarehouseid
,lproductid
,SUM(lqty) lqty
FROM ABBICS.iOrdPrdQtyDate
GROUP BY cvwarehouseid
,lproductid
)
SELECT
...
WHERE IORDREFILL.DNCONFIRMEDDELDATE < CAST(TO_CHAR(d.current_d , 'YYYYMMDD') AS NUMBER(38))
...
If I understand you correctly, you assume that you can only use 1 inline table per query. That is not true, you can use multiple inline tables and expand the existing WITH clause with another to loop through dates:
with OrderReserve as (
SELECT cvwarehouseid
,lproductid
,SUM(lqty) lqty
FROM ABBICS.iOrdPrdQtyDate
GROUP BY cvwarehouseid
,lproductid
), date_range as (
select sysdate+level
from dual
connect by level <= 30
)
select *
from OrderReserve, date_range
... -- expand with date_range as you see fit
;
I´m doing a paginated query using the following template:
select * from (select rownumber() over
( order by aaa.x ) as rownum, aaa.abc, aaa.bcd,bbb.cde from aaa as aaa
left join bbb on aaa.colx= bbb.coly where aaa.where1 = 'xxx'
) as tempresult where rownum between 101 and 200
Assuming a page size of 100 items, the first page query would be the same thing, replacing the rownum condition for:
where rownum <= 100
I´m facing a situation where the first page performs very well ( <1s ), but when we move from the second page-forward the query takes about 5-6s.
Can anyone explain me why is that the case?
Is there any way to slight modify this query template in order to achieve better performance?
Is there any complete different strategy that could perform better?
Additional Info:
I use DB2 v9.7.400.501
There´s no limit keyword
I cannot create views or stored procedures due to a customer constraint
I cannot create any additional indexes
Tried switching from rownumber() no rank() but it didnt change anything
You will need to look at both queries' execution plans to see if there is any difference -- only that can give you a definite answer.
You could try rewriting the query like so:
select * from (
select rownumber() over ( order by aaa.x ) as rownum, aaa.abc, aaa.bcd
from aaa as aaa
where aaa.where1 = 'xxx'
) as tempresult
left join bbb on tempresult.colx= bbb.coly
and tempresult.rownum between 101 and 200
Edit:
Nothing prevents you from using columns from bbb in the final select:
select tempresult.*, bbb.cde
from (
select rownumber() over ( order by aaa.x ) as rownum, aaa.abc, aaa.bcd
from aaa as aaa
where aaa.where1 = 'xxx'
) as tempresult
left join bbb on tempresult.colx= bbb.coly
and tempresult.rownum between 101 and 200
A weird request maybe but. My boss wants me to create an admin version of a page we have that displays data from an oracle query in a table.
The admin page, instead of displaying the data (query returns 1 row), needs to return the table name and column name
Ex: Instead of:
Name Initial
==================
Bob A
I want:
Name Initial
============================
Users.FirstName Users.MiddleInitial
I realize I can do this in code but would rather just modify the query to return the data I want so I can leave the report generation code mostly alone.
I don't want to do it in a stored procedure.
So when I spit out the data in the report using something like:
blah blah = MyDataRow("FirstName")
I can leave that as is but instead of it displaying "BOB" it would display "Users.FirstName"
And I want to do the query using select * if possible instead of listing all the columns
So for each of the columns I am querying in the * , I want to get (instead of the column value) the tablename.ColumnName or tablename|columnName
hope you are following- I am confusing myself...
pseudo:
select tablename + '.' + Columnname as WhateverTheColumnNameIs
from Table1
left join Table2 on whatever...
Join Table_Names on blah blah
Whew- after writing all this I think I will just do it on the code side.
But if you are up for it maybe a fun challenge
Oracle does not provide an authentic way(there is no pseudocolumn) to get the column name of a table as a result of a query against that table. But you might consider these two approaches:
Extract column name from an xmltype, formed by passing cursor expression(your query) in the xmltable() function:
-- your table
with t1(first_name, middle_name) as(
select 1,2 from dual
), -- your query
t2 as(
select * -- col1 as "t1.col1"
--, col2 as "t1.col2"
--, col3 as "t1.col3"
from hr.t1
)
select *
from ( select q.object_value.getrootelement() as col_name
, rownum as rn
from xmltable('//*'
passing xmltype(cursor(select * from t2 where rownum = 1))
) q
where q.object_value.getrootelement() not in ('ROWSET', 'ROW')
)
pivot(
max(col_name) for rn in (1 as "name", 2 as "initial")
)
Result:
name initial
--------------- ---------------
FIRST_NAME MIDDLE_NAME
Note: In order for column names to be prefixed with table name, you need to list them
explicitly in the select list of a query and supply an alias, manually.
PL/SQL approach. Starting from Oracle 11g you could use dbms_sql() package and describe_columns() procedure specifically to get the name of columns in the cursor(your select).
This might be what you are looking for, try selecting from system views USER_TAB_COLS or ALL_TAB_COLS.
I have two rows that have a varchar column that are different according to a Java .equals(). I can't easily change or debug the Java code that's running against this particular database but I do have access to do queries directly against the database using SQLDeveloper. The fields look the same to me (they are street addresses with two lines separated by some new line or carriage feed/new line combo).
Is there a way to see all of the hidden characters as the result of a query?I'd like to avoid having to use the ascii() function with substr() on each of the rows to figure out which hidden character is different.
I'd also accept some query that shows me which character is the first difference between the two fields.
Try
select dump(column_name) from table
More information is in the documentation.
As for finding the position where the character differs, this might give you an idea:
create table tq84_compare (
id number,
col varchar2(20)
);
insert into tq84_compare values (1, 'hello world');
insert into tq84_compare values (2, 'hello' || chr(9) || 'world');
with c as (
select
(select col from tq84_compare where id = 1) col1,
(select col from tq84_compare where id = 2) col2
from
dual
),
l as (
select
level l from dual
start with 1=1
connect by level < (select length(c.col1) from c)
)
select
max(l.l) + 1position
from c,l
where substr(c.col1,1,l.l) = substr(c.col2,1,l.l);
SELECT DUMP('€ÁÑ', 1016)
FROM DUAL
... will print something like:
Typ=96 Len=3 CharacterSet=WE8MSWIN1252: 80,c1,d1