I wanna pull a random entry in my database that has downloaded value as 0. How can I do this?
SELECT * FROM table WHERE downloaded=0 ORDER BY RANDOM() LIMIT 1;
Related
How to get a random row from a table in DBFlow?
In SQLite I would simply write the query as:
select * from table_name ORDER BY RANDOM() LIMIT 1;
Whats the equivalent for it? I couldn't find anything and OrderBy accepts only column values. Thank you.
My question is about DBFlow ORM for Android, not for SQLite.
I am trying to pull data starting from today, to last 10 transactions i.e. I am getting the first 10 transactions and then I want to apply scroll up / down to move to previous 10 / next 10 transactions.
SELECT * FROM table_transaction LIMIT 10
I tried the above query this gives a LIMIT of 10 starting from the top (Today's to last 10 transaction details)
How do I implement the above logic?
Can somebody help me fix this?
if you want get 10 starting from the top
SELECT * FROM table_transaction LIMIT 0,10
and if you want next 10 item:
SELECT * FROM table_transaction LIMIT 1,10
You can use the ROWID column of the sqlite tables. This column is automatically managed by the sqlite.
Sqlite Documantation
Use OrderBy Clause for geting last n number of transaction -
SELECT * FROM table_transaction LIMIT 10 ORDER BY COLUMN_NAME DESC
above query returns last 10 inserted transaction.
For Scrolling you have to create logic create an integer variable say 'last_order_id' and assign it to max order id.
In your query pass last order id and every time you execute query update 'last_order_id'.
So your updated query will be -
SELECT * FROM table_transaction LIMIT 10 ORDER BY COLUMN_NAME DESC INNER JOIN table_transaction.order_id<last_order_id;
hope it will help you.
I want to get the latest 5 records in my table, so far i tried this but, it did not work out very well. So, what is the cleanest and efficient way to get last 5 records in the table ?
"select * from (select * from People order by Date DESC limit 5) order by Date ASC;"
Your query works just fine.
To make it efficient, ensure that there is an index on the Date column; then SQLite will just read the last five entries from the index and the table and does not need to scan the entire table.
If this table has an autoincrementing ID column, and if "latest" means the insertion order, then you can use that ID for sorting; this will be as efficient as your original query with an index on Date:
SELECT * FROM (SELECT * FROM People
ORDER BY _id DESC
LIMIT 5)
ORDER BY Date ASC
I have a database wherein i get my questions , correct answers/options from... I want my application to automatically generate random rowIds so that the questions could be shuffled.. Of course, the question that's already shown should not display again. I want to get 10 questions then finish();..
Using a random rowId is the wrong approach. What if the database is modified and the ID becomes invalid? You'd have to check every ID and regenerate when an invalid ID comes up.
Instead, you should use a LIMIT clause in your SELECT statement with a random number less than the number of rows in the table.
No need to generate random ids first. Just insert your rows, making sure you have the questionId column.
When you want read your database. Do something like quizid = rand() ....
After that you select the row with quizid in your database
SELECT * FROM quiztable WHERE questionId = quizid
Something like that will give you a random row from your database.
I think you get the point.
I have a database having 28 rows just for saving app data. My goal is to read One specific column (not one value) from it.
However, I don't want to read all columns at once, because it's slow as I have blob's in db too. Instead, I'd like to read just one column at a time, separately. Can you plese help me to solve this problem.
If you want to read one ROW do something along those lines:
SELECT * FROM tablename WHERE id='5' LIMIT 1;
where 'id' is supposer do be in the table 'tablename'
or else try something like this:
SELECT datafield FROM tablename WHERE 1;
which will give you all the 'datafield' data from the table (ie. a Column).
If this doesn't help you at all then post the code you are already using.