选择SQLite中的随机行-Selectrandomrow(s)inSQLite

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For a much better performance use:

为了更好地使用性能:

SELECT * FROM table WHERE id IN (SELECT id FROM table ORDER BY RANDOM() LIMIT x)

SQL engines first load projected fields of rows to memory then sort them, here we just do a random sort on id field of each row which is in memory because it's indexed, then separate X of them, and find the whole row using these X ids.

SQL引擎首先将投影行的字段加载到内存中，然后对它们进行排序，这里我们只是对每个行的id字段进行随机排序，因为它是被索引的，然后将它们的X分开，然后使用这些X id找到整个行。

So this consume less RAM and CPU as table grows!

因此，随着表的增长，这消耗的RAM和CPU减少了!

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SELECT * FROM table ORDER BY RANDOM() LIMIT X

根据RANDOM() LIMIT X从表顺序中选择*

7  

SELECT * FROM table ORDER BY RANDOM() LIMIT 1

0  

All answers here are based on ORDER BY. This is very inefficient (i.e. unusable) for large sets. Why not just place abs(CAST(random() AS REAL))/9223372036854775808 <0.5 in the WHERE clause to get in this case 0.5 hit chance?

这里所有的答案都是基于ORDER BY。对于大型集合来说，这是非常低效的(即不能使用)。为什么不直接在WHERE子句中放置abs(CAST(random() AS REAL))/ 922337203685474775808 <0.5在这种情况下，命中概率为0.5 ?

SELECT *
FROM table
WHERE abs(CAST(random() AS REAL))/9223372036854775808 <0.5

The large number is the maximum absolute number that random() can produce. The abs() is because it is signed. Result is a uniformly distributed random variable between 0 and 1.

大数字是random()能生成的最大绝对值。abs()是因为它是有符号的。结果是0和1之间的均匀分布随机变量。