sqlite: Functions thats returns the values resulting from a 'SELECT' query and name of column - Feature ISSUE #20565

[viniciusfdasilva]

This pull request addresses the feature mentioned in issue #20565 and implements a function that returns the values resulting from a 'SELECT' query and the name of each column. If an alias is provided either through the 'as' command or not, the returned value becomes the alias.

'SELECT SYNTAX' - Documentation
'JOIN SYNTAX' - Documentation

Source code

Examples:

All fields

r := db.get_queryset('SELECT * FROM repository')! 

All names with explicit names

r := db.get_queryset('SELECT name, id FROM repository')!

All fields with alias

r := db.get_queryset('SELECT name as n, id i FROM repository')!

Specific field

r := db.get_queryset('SELECT name FROM repository')! 

Specific field with alias and 'as'

r := db.get_queryset('SELECT name as n FROM repository')! 

Specific field with alias without 'as'

r := db.get_queryset('SELECT name n FROM repository')! 

All tests are in: vlib/db/sqlite/sqlite_test.v

OUTPUT TESTS

[spytheman]

hm, why is regex matching needed at all?

[viniciusfdasilva]

I use the string query itself to obtain the names of the columns if they have been specified, as well as the name of the table! Since there are several ways to initiate the 'SELECT' command doc, I constructed a regex based on the syntax to facilitate obtaining the column names and the table name!

[spytheman]

rows := db.exec(query)! will return an error itself, if the query has invalid syntax.

[viniciusfdasilva]

Correct, that's why I don't perform any verification other than simply checking if the query is a "select" statement beforehand. If the query isn't a select statement, I don't execute it at all!

That way, I save execution time for a query that isn't even a 'select'.