Select random row from Safaris client-side databas

问题:

I'm experimenting with the built in SQL support in the Safari Browser and I want to select a random query via Javascript.

SELECT * FROM questions ORDER BY random()

Returns not authorized to use function: random

See this screenshot.

Any suggestions?

回答1:

Query using a non-random order, then shuffle the results:

tx.executeSql('SELECT * FROM questions',[], function(tx, resultSet) {
    var resultArray = [];

    for(var i=0; i < resultSet.rows.length; i+=1) {
        resultArray.push(resultSet.rows.item(i));
    }

    var shuffledArray = shuffle(resultArray);

    // do something with the shuffled array...
});

Where shuffle() could be something like this: https://stackoverflow.com/a/962890/490560

回答2:

Perhaps something like the following would work:

SELECT *
  FROM (SELECT RANDOM() as RANDOM_NUM, Q.*
          FROM QUESTIONS Q)
  ORDER BY RANDOM_NUM

Share and enjoy.