SQLITE是否可以计算最长递增子序列的长度，也称为排序百分比？

Question

With the latest version of Sqlite, Is it possible to calculate the length of the longest increasing subsequence, also referred to as sortation percent, using a sqlite UDF, user defined function?

October 15,2012 edit as requested by @Code-Guru.

Following the project gurus's example sequence of -- 1,2,3,4,3,5,6,7,8,10 -- the numeric sorted ascending subsequence is found to be 1,2,3,4,5,6,7,8,10 using an automatic variable containing the most recent monotically increasing sequence member value and traversing the array sequentially. As a result, the length of the sorted numeric ascending subsequence is 9. The length of the entire sequence is 10. So, the sortation percentage is (9/10) * 100% = 90%. Thank you.

Answer 1

Sqlite does not have any functionality that implements longest increasing subsequence, so you will need a user defined function

You can sort by function results. I don't believe UDFs are treated any differently in this respect.

Here is an example of how you would use a function (user defined or not) to order your query results.

sqlite> create table foo(a);
sqlite> create table foobar(a);
sqlite> create table fubar(a);
sqlite> select name, length(name) as len from sqlite_master;
foo|3
foobar|6
fubar|5
sqlite> select name, length(name) as len from sqlite_master order by len;
foo|3
fubar|5
foobar|6