Android sort sqlite query results ignoring case - android

just wondering if theres a way of sorting the results of a query ignoring case. Cause at the moment fields starting with an upper case letter are sorted and put on top of the list and fields starting with lower case letter are also sorted but are put after the upper case fields.
Thanks --
Mike

ORDER BY column COLLATE NOCASE;
See http://www.sqlite.org/datatype3.html#collation

On the Android you are given a collation function called LOCALIZED.
When you specify your column, do the following:
CREATE TABLE song(..., title TEXT COLLATE LOCALIZED ASC, ...)
It works great. If you have the Android source code, just do a search for "COLLATE" to see all sorts of examples.

Convert all entries to lower case for example: select name from table order by LCASE(name)
LCASE or LOWER (Check documentation)

Related

Natural sorting of alphanumeric values in sqlite using android

I have a list of names of starts with characters and end with numbers like: -
ka1, ka10, ka 2, ka, sa2, sa1, sa10, p1a10, 1kb, p1a2, p1a11, p1a.
I want to sort it in natural order, that is: -
1kb, ka, ka1, ka 2, ka10, p1a, p1a2, p1a10, p1a11, sa1, sa2, sa10.
The main problem I am seeing here is no delimiter between text and numeric part, there also a chance of without numeric part also.
I am using sqlite in android, I can do sorting using java after fetching points by cacheing cursor data, but I am using(recommended to use) cursor adapter.
Please suggest a query for sorting or is there any way to apply sorting in cursor?
I tried below query for Natural sorting:
SELECT
item_no
FROM
items
ORDER BY
LENGTH(item_no), item_no;
It worked for me in Sqlite db too. Please see this link, for more details.
I can propose using regex replacement adding zeros, creating temporary table of original and corresponding values, then follow this link for sorting it: http://www.saltycrane.com/blog/2007/12/how-to-sort-table-by-columns-in-python/
tip for regex add as many zeros after last letter, but limit the number of total digits for predicted maximum number of digits. If You need help with regex as well, provide exact info of valid and invalid values, so can halp with that too.
PS if want to be sure that zeros goes before last digits search for char from the end
Updated
You can use different ways - Some of are mentioned below:
BIN Way
SELECT
tbl_column,
BIN(tbl_column) AS binray_not_needed_column
FROM db_table
ORDER BY binray_not_needed_column ASC , tbl_column ASC
Cast Way
SELECT
tbl_column,
CAST(tbl_column as SIGNED) AS casted_column
FROM db_table
ORDER BY casted_column ASC , tbl_column ASC
or try the solution:
There are a whole lot of solutions out there if you hit up Google, and
you can, of course, just use the natsort() function in PHP, but it's
simple enough to accomplish natural sorting in MySQL: sort by length
first, then the column value.
Query: SELECT alphanumeric, integer FROM sorting_test ORDER BY LENGTH(alphanumeric), alphanumeric from here

Combine MATCH with OR clause in the WHERE statement

I want to perform a query in which the WHERE clausule has the following condition:
one MATCH condition over a column in a FTS3 table
OR
another not MATCH condition over a column in a non FTS table.
Example:
Say that I have two tables
books_fts, which is a table with a content column for full text search.
books_tags, which is non FTS table with tags.
I want to search all the books that either contain 'Dikjstra' in their content or are tagged with the 'algorithm' word. So I run this query:
SELECT * from books_fts
LEFT OUTER JOIN books_tags ON books_fts.fk_id = books_tags.id
WHERE (books_fts MATCH 'content:%Dijkstra*')
OR (books_tags.tag = 'algorithm')
I think the query is right, and if I run it with either one of the OR clausules, it works.
However, when running it with the two clausules I get the following error:
unable to use function MATCH in the requested context
Seems to me that I cannot combine a MATCH with a non MATCH in the WHERE clause, even if each of them apply to different tables (one FTS and another non FTS).
Is this true? I cannot find information on it.
NOTE: if the causules are separated with AND instead of OR the query is valid.
Thanks.
It seems it's a known issue in SQL:
http://sqlite.1065341.n5.nabble.com/FTS3-bug-with-MATCH-plus-OR-td50714.html

SQLite select statement is not working when a column contains the '?' or the 'x' character

I noticed that whenever I try to execute an sqlite query on a column that contains strings in which the '?' (due to encoding errors) or the 'x' character is contained, the matching fails.
Does anyone know why? I suspect the second case has something to do with the relative hexadecimal symbol. This holds for either sqlite version 3.7.9 and 3.8.6.
Thanks in advance
Edit:
SELECT FM.Foodname FROM Foodtable AS FM WHERE Foodname MATCH 'Alom*' UNION ALL SELECT F2.Foodname FROM Foods_units_2 AS F2 JOIN Foodtable ON Foodtable.Foodname = F2.Foodname ORDER BY F2.Foodname;
The problem is withe last statement (Foodtable.Foodname = F2.Foodname) where the Foodtable contains all records and Foods_units_2 contains part of records with different units of measurement. In both tables there are Foodname strings that contain the characters '?' (due to encoding errors) and 'x'. In thoses cases the matching fails and sqlite replaces the wrong strings with others
For example in the first case I have "Cr?me Kαραμελέ" where '?' is supposed to be 'è' and in the second case "4?4 compact" where '?' is supposed to be 'x'.
Well, I think I made a mistake. The reason the matching failed was because the main table included records where '?' was present (encoding errors), while Foods_units_2 table did not.
Anyway, hank you guys for your promptness and sorry for the inconvenience.

Search data from sqlite3 database in android

I have a Sqlite3 database in android, with data are sentences like: "good afternoon" or "have a nice day", now I want to have a search box, to search between them, I use something like this :
Cursor cursor = sqliteDB.rawQuery("SELECT id FROM category WHERE sentences LIKE '"+ s.toString().toLowerCase()+ "%' LIMIT 10", null);
But it only show "good afternoon" as result if user start searching with first "g" or "go" or "goo" or etc, how can I retrieve "good afternoon" as results, if user search like "a" or "af" or "afternoon".
I mean I want to show "good afternoon" result, if user search from middle of a data in sqlite3 db, not only if user searches from beginning.
thanks!
Just put the percent sign in front of your query string: LIKE '%afternoon%'. However, your approach has two flaws:
It is susceptible to SQL injection attacks because you just insert unfiltered user input into your SQL query string. Use the query parameter syntax instead by re-writing your query as follows:
SELECT id FROM category WHERE sentences LIKE ? LIMIT 10. Add the user input string as selection argument to your query method call
It will be dead slow the bigger your database grows because LIKE queries are not optimized for quick string matching and lookups.
In order to solve number 2 you should use SQLite's FTS3 extension which greatly speeds up any text-related searches. Instead of LIKE you would be using the MATCH operator that uses a different query syntax:
SELECT id FROM category WHERE sentences MATCH 'afternoon' LIMIT 10
As you can see the MATCH operator does not need percent signs. It just tries to find any occurrence of a word in the whole text that is being searched (in your case the sentences column). Read through the documentation of FTS3 I've linked to. The MATCH query syntax provides some more pretty handy and powerful options for finding text in your database table which are pretty similar to early search engine query syntax such as:
MATCH 'afternoon OR evening'
The only (minor) downside to the FTS3 extension is that it blows up the database file size by creating additional search index tables and meta-data. But I think it's well worth it for this use case.

Android: sqlite: cursor: getColumnIndex

I've got a fairly complicated query (multiple joins) on a normalized sqlite database. The query does a SELECT * to enable some automated attribute selection logic (so I can't eliminate the "*")
The problem I am having is that my result set contains multiple columns with the same attribute name. For example, one attribute common to each table in the query is "_id". When I go to call "cursor.getColumnIndex("_id")" the value returned is always the index of the last "_id" attribute in the result set column list (i.e. not the one I want). I'd love to be able to use my SQL alias prefixes like cursor.getColumnIndex("A._id") but that is not working.
QUESTIONs
It appears that cursor.getColumnIndex(AttributeName) returns the index of the last "AttributeName". Can anyone confirm this?
Also, any suggestions on how return the index of the 1st attribute with "AttributeName"? or better the Xth attribute having "AttributeName"?
You can do this:
SELECT _id as myID, * FROM myTable
This means the _id field will appear twice for each table in your results, but one of the two columns will have a unique name which should enable you to find it.
Unfortunately the documentation doesn't mention anything about what you need to do, so I am assuming it cannot be done.
However, you say
The query does a SELECT * to enable some automated attribute selection
logic (so I can't eliminate the "*")
What is this 'automated attribute selection logic' you speak of? Why do you require this?
An oder solution is:
"SELECT tableName.columnName FROM tableName"
and then do the same with:
cursor.getColumnIndex("tableName.columnName");
This is what MS-Access does. You can create a query and then see the generated SQL code (simply going to 'view' menu and selecting 'SQL view' from your query dessign window)

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