Using LIKE in an Oracle IN clause - sql

I know I can write a query that will return all rows that contain any number of values in a given column, like so:
Select * from tbl where my_col in (val1, val2, val3,... valn)
but if val1, for example, can appear anywhere in my_col, which has datatype varchar(300), I might instead write:
select * from tbl where my_col LIKE '%val1%'
Is there a way of combing these two techniques. I need to search for some 30 possible values that may appear anywhere in the free-form text of the column.
Combining these two statements in the following ways does not seem to work:
select * from tbl where my_col LIKE ('%val1%', '%val2%', 'val3%',....)
select * from tbl where my_col in ('%val1%', '%val2%', 'val3%',....)

What would be useful here would be a LIKE ANY predicate as is available in PostgreSQL
SELECT *
FROM tbl
WHERE my_col LIKE ANY (ARRAY['%val1%', '%val2%', '%val3%', ...])
Unfortunately, that syntax is not available in Oracle. You can expand the quantified comparison predicate using OR, however:
SELECT *
FROM tbl
WHERE my_col LIKE '%val1%' OR my_col LIKE '%val2%' OR my_col LIKE '%val3%', ...
Or alternatively, create a semi join using an EXISTS predicate and an auxiliary array data structure (see this question for details):
SELECT *
FROM tbl t
WHERE EXISTS (
SELECT 1
-- Alternatively, store those values in a temp table:
FROM TABLE (sys.ora_mining_varchar2_nt('%val1%', '%val2%', '%val3%'/*, ...*/))
WHERE t.my_col LIKE column_value
)
For true full-text search, you might want to look at Oracle Text: http://www.oracle.com/technetwork/database/enterprise-edition/index-098492.html

A REGEXP_LIKE will do a case-insensitive regexp search.
select * from Users where Regexp_Like (User_Name, 'karl|anders|leif','i')
This will be executed as a full table scan - just as the LIKE or solution, so the performance will be really bad if the table is not small. If it's not used often at all, it might be ok.
If you need some kind of performance, you will need Oracle Text (or some external indexer).
To get substring indexing with Oracle Text you will need a CONTEXT index. It's a bit involved as it's made for indexing large documents and text using a lot of smarts. If you have particular needs, such as substring searches in numbers and all words (including "the" "an" "a", spaces, etc) , you need to create custom lexers to remove some of the smart stuff...
If you insert a lot of data, Oracle Text will not make things faster, especially if you need the index to be updated within the transactions and not periodically.

No, you cannot do this. The values in the IN clause must be exact matches. You could modify the select thusly:
SELECT *
FROM tbl
WHERE my_col LIKE %val1%
OR my_col LIKE %val2%
OR my_col LIKE %val3%
...
If the val1, val2, val3... are similar enough, you might be able to use regular expressions in the REGEXP_LIKE operator.

Yes, you can use this query (Instead of 'Specialist' and 'Developer', type any strings you want separated by comma and change employees table with your table)
SELECT * FROM employees em
WHERE EXISTS (select 1 from table(sys.dbms_debug_vc2coll('Specialist', 'Developer')) mt
where em.job like ('%' || mt.column_value || '%'));
Why my query is better than the accepted answer: You don't need a CREATE TABLE permission to run it. This can be executed with just SELECT permissions.

In Oracle you can use regexp_like as follows:
select *
from table_name
where regexp_like (name, '^(value-1|value-2|value-3....)');
The caret (^) operator to indicate a beginning-of-line character &
The pipe (|) operator to indicate OR operation.

This one is pretty fast :
select * from listofvalue l
inner join tbl on tbl.mycol like '%' || l.value || '%'

Just to add on #Lukas Eder answer.
An improvement to avoid creating tables and inserting values
(we could use select from dual and unpivot to achieve the same result "on the fly"):
with all_likes as
(select * from
(select '%val1%' like_1, '%val2%' like_2, '%val3%' like_3, '%val4%' as like_4, '%val5%' as like_5 from dual)
unpivot (
united_columns for subquery_column in ("LIKE_1", "LIKE_2", "LIKE_3", "LIKE_4", "LIKE_5"))
)
select * from tbl
where exists (select 1 from all_likes where tbl.my_col like all_likes.united_columns)

I prefer this
WHERE CASE WHEN my_col LIKE '%val1%' THEN 1
WHEN my_col LIKE '%val2%' THEN 1
WHEN my_col LIKE '%val3%' THEN 1
ELSE 0
END = 1
I'm not saying it's optimal but it works and it's easily understood. Most of my queries are adhoc used once so performance is generally not an issue for me.

select * from tbl
where exists (select 1 from all_likes where all_likes.value = substr(tbl.my_col,0, length(tbl.my_col)))

You can put your values in ODCIVARCHAR2LIST and then join it as a regular table.
select tabl1.* FROM tabl1 LEFT JOIN
(select column_value txt from table(sys.ODCIVARCHAR2LIST
('%val1%','%val2%','%val3%')
)) Vals ON tabl1.column LIKE Vals.txt WHERE Vals.txt IS NOT NULL

You don't need a collection type as mentioned in https://stackoverflow.com/a/6074261/802058. Just use an subquery:
SELECT *
FROM tbl t
WHERE EXISTS (
SELECT 1
FROM (
SELECT 'val1%' AS val FROM dual
UNION ALL
SELECT 'val2%' AS val FROM dual
-- ...
-- or simply use an subquery here
)
WHERE t.my_col LIKE val
)

Related

DB2 efficient select query with like operator for many values (~200)

I have written the following query:
SELECT TBSPACE FROM SYSCAT.TABLES WHERE TYPE='T' AND (TABNAME LIKE '%_ABS_%' OR TABNAME LIKE '%_ACCT_%')
This gives me a certain amount of results. Now the problem is that I have multiple TABNAME to select using the LIKE operator (~200). Is there an efficient way to write the query for the 200 values without repeating the TABNAME LIKE part (because there are 200 such values which would result in a really huge query) ?
(If it helps, I have stored all required TABNAME values in a table TS to retrieve from)
If you are just looking for substrings, you could use LOCATE. E.g.
WITH SS(S) AS (
VALUES
('_ABS_')
, ('_ACCT_')
)
SELECT DISTINCT
TABNAME
FROM
SYSCAT.TABLES, SS
WHERE
TYPE='T'
AND LOCATE(S,TABNAME) > 0
or if your substrings are in table CREATE TABLE TS(S VARCHAR(64))
SELECT DISTINCT
TABNAME
FROM
SYSCAT.TABLES, TS
WHERE
TYPE='T'
AND LOCATE(S,TABNAME) > 0
You could try REGEXP_LIKE. E.g.
SELECT DISTINCT
TABNAME
FROM
SYSCAT.TABLES
WHERE
TYPE='T'
AND REGEXP_LIKE(TABNAME,'.*_((ABS)|(ACCT))_.*')
Just in case.
Note, that the '_' character has special meaning in a pattern-expression of the LIKE predicate:
The underscore character (_) represents any single character.
The percent sign (%) represents a string of zero or more characters.
Any other character represents itself.
So, if you really need to find _ABS_ substring, you should use something like below.
You get both rows in the result, if you use the commented out pattern instead, which may not be desired.
with
pattern (str) as (values
'%\_ABS\_%'
--'%_ABS_%'
)
, tables (tabname) as (values
'A*ABS*A'
, 'A_ABS_A'
)
select tabname
from tables t
where exists (
select 1
from pattern p
where t.tabname like p.str escape '\'
);

select TableData where ColumnData start with list of strings

Following is the query to select column data from table, where column data starts with a OR b OR c. But the answer i am looking for is to Select data which starts with List of Strings.
SELECT * FROM Table WHERE Name LIKE '[abc]%'
But i want something like
SELECT * FROM Table WHERE Name LIKE '[ab,ac,ad,ae]%'
Can anybody suggest what is the best way of selecting column data which starts with list of String, I don't want to use OR operator, List of strings specifically.
The most general solution you would have to use is this:
SELECT *
FROM Table
WHERE Name LIKE 'ab%' OR Name LIKE 'ac%' OR Name LIKE 'ad%' OR Name LIKE 'ae%';
However, certain databases offer some regex support which you might be able to use. For example, in SQL Server you could write:
SELECT *
FROM Table
WHERE NAME LIKE 'a[bcde]%';
MySQL has a REGEXP operator which supports regex LIKE operations, and you could write:
SELECT *
FROM Table
WHERE NAME REGEXP '^a[bcde]';
Oracle and Postgres also have regex like support.
To add to Tim's answer, another approach could be to join your table with a sub-query of those values:
SELECT *
FROM mytable t
JOIN (SELECT 'ab' AS value
UNION ALL
SELECT 'ac'
UNION ALL
SELECT 'ad'
UNION ALL
SELECT 'ae') v ON t.vame LIKE v.value || '%'

Using CONTAINS to find items IN a table

I'm trying to write a SP that will allow users to search on multiple name strings, but supports LIKE functionality. For example, the user's input might be a string 'Scorsese, Kaurismaki, Tarkovsky'. I use a split function to turn that string into a table var, with one column, as follows:
part
------
Scorsese
Kaurismaki
Tarkovsky
Then, normally I would return any values from my table matching any of these values in my table var, with an IN statement:
select * from myTable where lastName IN (select * from #myTableVar)
However, this only returns exact matches, and I need to return partial matches. I'm looking for something like this, but that would actually compile:
select * from myTable where CONTAINS(lastName, select * from #myTableVar)
I've found other questions where it's made clear that you can't combine LIKE and IN, and it's recommended to use CONTAINS. My specific question is, is it possible to combine CONTAINS with a table list of values, as above? If so, what would that syntax look like? If not, any other workarounds to achieve my goal?
I'm using SQL Server 2016, if it makes any difference.
You can use EXISTS
SELECT * FROM myTable M
WHERE
EXISTS( SELECT * FROM #myTableVar V WHERE M.lastName like '%'+ V.part +'%' )
Can your parser built the entire statement? Will that get you what you want?
select *
from myTable
where CONTAINS
(lastName,
'"Scorsese" OR "Kaurismaki" OR "Tarkovsky"'
)
This can be done using CHARINDEX function combined with EXISTS:
select *
from myTable mt
where exists(select 1 from #myTableVar
where charindex(mt.lastName, part) > 0
or charindex(part, mt.lastName) > 0)
You might want to omit one of the conditions in the inner query, but I think this is what you want.

How to use multiple values with like in sql

select * from user_table where name in ('123%','test%','dummy%')
How to ensure that this where clause is not an exact match, but a like condition?
In Oracle you can use regexp_like as follows:
select *
from user_table
where regexp_like (name, '^(123|test|dummy)')
The caret (^) requires that the match is at the start of name, and the pipe | acts as an OR.
Be careful though, because with regular expressions you almost certainly lose the benefit of an index that might exist on name.
Use like this,
select *
from user_table
where name LIKE '123%'
OR name LIKE 'test%'
OR name Like 'dummy%';
another option in MySQL
select * from user_table where name REGEXP '^123|^test|^dummy';
To not lose indexed access to rows in Oracle a table collection expression can be used:
SELECT
*
FROM
user_table
JOIN (SELECT column_value filter
FROM table(sys.odcivarchar2list('dummy%', '123%', 'test%'))
) ON user_table.name LIKE filter
The filter expressions must be distinct otherwise you get the same rows from user_table multiple times.

How to use LIKE with ANY in Postgresql?

Is there a way to do a partial string match on a string array column in postgres?
I'm trying the following syntax, but it is not working as I'd expect it to:
SELECT * FROM example_table WHERE '%partial string' ILIKE ANY(array_column)
Is there a correct way of doing this?
drop table if exists temp_a;
create temp table temp_a as
(
select array['alpha','beta'] as strings
union all
select array['gamma','theta']
);
select *
from (select unnest(strings) as string from temp_a) as sq
where string ilike '%eta'
You need to search each subscript separately -- here's an example that can be expounded on to include more columns
SELECT distinct array_column FROM
(SELECT array_column,
generate_subscripts(array_column, 1) AS s
FROM example_table) AS foo
WHERE array_column[s] like '%partial string';
Alternative hack:
select * from example_table where array_column::text like '%partial%'
if necessary you could hack "partial" to include the opening/closing brackets and quotes to be just a bit more precise.
Just implemented this using array_to_string:
SELECT * FROM example_table WHERE array_to_string(array_column) ILIKE '%partial string'