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0answers
15 views

Which benchmark assess string pattern matching in a database?

I have a postgresql DB in which I do a lot of string matching ala : UPDATE table1 SET colum1 = TRUE WHERE colum2 LIKE '%teststring%'; colum2 is a whole html file As I said I do A LOT of this and ...
0
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1answer
32 views

Mixed search in multiple columns

I have a table which has a particular column of type JSON, where some user's contact information are stored. I can alter the table and add new columns with cached values to increase search performance ...
0
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1answer
289 views

PostgreSQL FTS and Trigram-similarity Query Optimization

I have recently started working on PostgreSQL and I have around 12M rows to handle in which I want to apply Full Text Search. I don't have any prior experience in handling such databases. I have tried ...
2
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3answers
416 views

How to query efficiently from Postgres to select special words?

Let's say that I have a table called words with very many records. Columns are id and name. In the words table I have for example: 'systematic', 'سلام','gear','synthesis','mysterious', etc. NB: ...
1
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1answer
268 views

Finding rows where a column contains [ and ] characters

I need to get results where the column contains a string that includes [ ]. When I use LIKE, it takes the [] as a wildcard sequence, and doesn't work as I need. For example, I want to search through ...
4
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1answer
757 views

Why would you index text_pattern_ops on a text column?

Today Seven Databases in Seven Weeks introduced me to per-operator indexes. You can index strings for pattern matching the previous queries by creating a text_pattern_ops operator class index, as ...
0
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1answer
81 views

Merge two tables on partly matching column

I have below 2 tables. old_name old_value Tom1 100 Kate1 80 Jim1 70 new_name new_value Tom2 70 Kate2 100 Jim2 80 I want to make a new table look like ...
1
vote
1answer
305 views

Using like over charindex to search for pattern

We where using charindex to search for a string as shown below SELECT * FROM tablename WHERE ( Charindex('47a%$.abc',CAST(columnname AS VARCHAR(MAX)))>0 ) I am planning to replace charindex with ...
1
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2answers
2k views

MYSQL matching one column to another in a different table via a FULLTEXT index

I current have two different tables. The first table has a list of titles and IDs associated to these titles, the second table is a list of random heading. What I would like to know is if there is a ...
7
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1answer
960 views

Algorithm for finding the longest prefix

I have two tables. First one is a table with prefixes code name price 343 ek1 10 3435 nt 4 3432 ek2 2 Second is call records with phone numbers number time 834353212 10 ...
0
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1answer
146 views

String replace using concatenated strings from various columns

I'd like to remove a substring in a column via update statement. The substring to replace consists of multiple strings from other different columns but in strict order. The specification says: ...
1
vote
2answers
508 views

Dropping a group of schemas with similar name patterns

Consider a situation where one need to perform a bunch of essentially identical operations, with the only variable being the name of some object. In my case, I need to drop some schemas, all of the ...
1
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0answers
64 views

PostgreSQL Fuzzymatching Error

I get such errors when using these functions, what's is wrong? pgdb=# SELECT distance('foo','zoo'); ERROR: parse error - invalid geometry LINE 1: SELECT distance('foo','zoo'); ...
0
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1answer
434 views

PostgreSQL 8.4 no levenshtein fuzzymatching?

I'm using debian squeeze package, it says function does not exist?
2
votes
1answer
224 views

Pattern similarity in time-series [closed]

I have a PostgreSQL database and my data-set include time-series of temperature for two stations. I would like to look their pattern's similarity in similar time sequences. For station number 1: ...
15
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4answers
12k views

Pattern matching with LIKE, SIMILAR TO or regular expressions in PostgreSQL

I had to write a simple query where I go looking for people's name that start with a B or a D : SELECT s.name FROM spelers s WHERE s.name LIKE 'B%' OR s.name LIKE 'D%' ORDER BY 1 I was wondering ...
4
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1answer
1k views

Alternatives to LIKE and FTS for mid name search

I have a question about what are the alternatives for LIKE '%%' and Full-Text Search when it comes to searching organisation names, firstnames, surnames, etc. The LIKE '%%' causes table scan, however ...
2
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2answers
2k views

Sort by match of LIKE

I wondering how I can implement SQL to get results sorted by best match of a like predicate. I have 100K articles in the database and when user call some items by part of name. I want to show the ...
9
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3answers
2k views

How is LIKE implemented?

Can anyone explain how the LIKE operator is implemented in current database systems (e.g. MySQL or Postgres)? or point me to some references that explain it? The naive approach would be to inspect ...
6
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3answers
4k views

LIKE to select the independent existence of the word whereever in the text

I have a table with the following texts and the key word i am searching for is 'Search'.So i have written a query SELECT [ID] ,[TextValue] FROM [dbo].[SearchLike] WHERE [TextValue] LIKE ...