I am using DB Browser for SQLite. The documentation for SQLite's fts3 says "FTS is primarily designed to support Boolean full-text queries". I built a virtual table using fts4 and successfully executed a few WHERE ... MATCH queries. But the following attempts give errors:
SELECT id FROM histsearch WHERE id MATCH ("-1456" IN BOOLEAN MODE);
SELECT id FROM histsearch WHERE NOT EXIST id MATCH ("1457");
Is the problem in DB Browser or in SQLite? How else can I write this query so it will work?
SQLite's full text service (fts3) basically offers Boolean Mode by default, no search modifier needed. DB Browser uses fts's standard query syntax, so NOT is not supported. To exclude a term, do something like
SELECT * FROM indexed WHERE indexed MATCH 'sqlite -database';
Edit: however, you cannot only exclude search terms in fulltext search:
An FTS query may not consist entirely of terms or term-prefix queries with unary "-" operators attached to them.
You'll have to use NOT LIKE for that.
Related
The SQLite FTS5 docs say that search queries such as SELECT ... WHERE MATCH '<query1> NOT <query2>' are supported, but it looks like there's no support for the unary NOT operator.
For example, if I want to search for everything that doesn't match <query>, I cannot use MATCH 'NOT <query>'. I would have to use NOT MATCH '<query>', which is a completely different thing (the FTS5 module never gets to see the NOT operator, as it is outside the quotation marks). Only the text inside the quotation marks is the search query.
I need to find a way to use an unary NOT operator inside the search query. I can't use it outside, because I only get to control the search query text, and not the rest of the SQL statement.
A possible approach I've thought of would be to find a search query that matches anything, and do MATCH '<match_anything> NOT <query>'. However, I've found no way to match everything in a search query.
Can you think of a way to have the behaviour of the unary NOT operator inside the search query?
Try this ..
SELECT * FROM docs
WHERE ROWID NOT IN (
SELECT ROWID FROM docs WHERE content MATCH '<query>'
)
I am working with SQLite. I need to know a query that retrieves all KEYWORDS in SQLite. Ex:
For Oracle: select * from v$reserved_words
For MySQL: select * from mysql.help_keyword
Above query will show all keywords in the corresponding database. Like this, I need a query for SQLite. Anyone knows please let me know.
There is no way to dynamically retrieve the list of reserved words, with a system table or a pragma.
The documentation lists the (currently) 124 keywords. It seems that the actual list also depends on the compile-time options.
I am trying to perform queries using the OR operator as following:
MapReduceResult result = riakClient.
mapReduce("some_bucket", "Name:c1 OR c2").
addMapPhase(new NamedJSFunction("Riak.mapValuesJson"), true).
execute();
I only get the 1st object in the query (where name='c1').
If I change the order of the query (i.e. Name:c2 OR c1) again I get only the first object in query (where name='c2').
is the OR operator (and other query operators) supported in the java client?
I got this answer from Basho engeneer, Sean C.:
You either need to group the terms or qualify both of them. Without a field identifier, the search query assumes that the default field is being searched. You can determine how the query will be interpreted by using the 'search-cmd explain' command. Here's two alternate ways to express your query:
Name:c1 OR Name:c2
Name:(c1 OR c2)
both options worked for me!
Sqlite3's full text search facility - FTS3 - allows to use MATCH operator for fast full-text search:
SELECT ItemId FROM docs WHERE docs.text MATCH 'linux'
However, it does not support OR operator anywhere in an SQL query where there's a MATCH (source: 1, 2):
SELECT ItemId FROM docs WHERE docs.text MATCH 'linux' OR column=value
error: unable to use function MATCH in the requested context
(Not to be confused with OR operator in the FTS3 query itself, i.e. SELECT ItemId FROM docs WHERE docs.text MATCH 'linux OR unix'. This works fine.)
Is there a way to rewrite the query so that it works (even if it's somewhat slower)?
Rewriting the query using temporary views will work as expected:
CREATE TEMP VIEW view1 AS SELECT ItemId FROM docs WHERE docs.text MATCH 'linux'
SELECT * FROM docs WHERE ItemId IN view1 OR column=value
DROP VIEW view1
The speed will be comparable to that of a "direct" query (without the temporary view) if the temporary view is not "sweeping", i.e. it does not generate a lot of rows.
I've got a search box that users can type terms into. I have a table setup with fulltext searching on a string column. Lets say a user types this: "word, office, microsoft" and clicks "search".
Is this the best way to deal with multiple search terms?
(pseudocode)
foreach (string searchWord in searchTerms){
select col1 from myTable where contains(fts_column, ‘searchWord’)
}
Is there a way of including the search terms in the sql and not iterating? I'm trying to reduce the amount of calls to the sql server.
FREETEXT might work for you. It will separate the string into individual words based on word boundaries (word-breaking). Then you'd only have a single SQL call.
MSDN -- FREETEXT
Well you could just build your SQL Query Dynamically...
string [] searchWords = searchTerm.Split(",");
string SQL = "SELECT col1 FROM myTable WHERE 1=2";
foreach (string word in searchWords)
{
SQL = string.Format("{0} OR contains(fts_column, '{1}')", SQL, word);
}
//EXEC SQL...
Obviously this comes with the usual warnings/disclaimers about SQL Injection etc... but the principal is that you would dynamically build up all your clauses and apply them in one query.
Depending on how your interacting with your DB, it might be feasible for you to pass the entire un-split search term into a SPROC and then split & build dynamic SQL inside the stored procedure.
You could do it similar to what you have there: just parse the search terms based on delimiter, and then make a call on each, joining the results together. Alternatively, you can do multiple CONTAINS:
SELECT Name FROM Products WHERE CONTAINS(Name, #Param1) OR CONTAINS(Name, #Param2) etc.
Maybe try both and see which is faster in your environment.
I use this class for Normalizing SQL Server Full-text Search Conditions