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Sqlite order by string of numbers7/14/2023 ![]() What I'm trying to say is that it's not particularly important to memorize function names as long as you know what can be done – and how they fit in the general SQL syntax – you'll easily remember the useful functions. But the number of core functions in SQLite isn't huge, and of those, I probably know a dozen and use just a handful in 95% of the situations. Since you can define your own functions in SQLite – something I've never actually tried – there are theoretically an unlimited number of functions to utilize and memorize. number of characters in the name – then by the count field, from largest to smallest: SELECT name, count FROM baby_names ORDER BY LENGTH ( name ) DESC, count DESC LIMIT 5 The following query uses the LENGTH function to orders names by longest to shortest – i.e. We know that we can ORDER BY columns, so it logically follows that we can also ORDER BY the results of functions on columns. (Hopefully this makes it very clear that the UPPER function does not transform the original data, if I haven't repeated myself enough on that point) Transforming values in the ORDER BY clauseįunctions can be used anywhere that column identifiers are used. Take note how the function is only applied in the WHERE clause the name value that is returned by the query for display is unaffected, i.e. in the WHERE clause: SELECT * FROM baby_names WHERE UPPER ( name ) = 'BILLY' LIMIT 5 (Again, the original data in the name column is left unchanged) Transforming values in the WHERE clauseįunctions can be used to transform values that are conditionally tested, i.e. ![]() ![]() Here are functions applied to the string 'hello': SELECT 'hello', LENGTH ( 'hello' ), UPPER ( 'hello' ) įunctions can also be applied to columns: SELECT name, LENGTH ( name ), UPPER ( name ) FROM baby_names LIMIT 1 Where can functions be used? Functions can be used wherever a column identifier or value is used.īefore we get to the list of functions themselves, here's a few quick examples of how and where functions are used. (Basically, SELECT statements will never change the underlying data) For example, if we were to run UPPER on the name column of baby_names, the results will contain upper-cased versions of each name value. It's important to know that while functions return a transformed version of their input, they do not modify the original data. The output should look like this: UPPER('hello there') Run the snippet above in your SQL client. As you can guess from the name UPPER, the new text string will consist of upper-cased letters. The UPPER function returns a new text string that is the transformation of 'hello there'. The argument – the text string, 'hello there' – is enclosed in parentheses in the function call: SELECT UPPER ( 'hello there' ) The values that we pass into a function as input are usually referred to as arguments (though sometimes I'll just say "input value").īelow is an example of the UPPER function. The functions we work with will each have a defined keyword, e.g. Basic definition and syntax of a functionįirst, some definitions: For the purposes of this tutorial, a function refers to a chunk of code that can act upon values passed into it. My main intent is for you to know how to just use functions. In this lesson, I list virtually all of what I would consider the kind-of-infrequently to frequently-used functions for the average user – and then a few more. ![]() It's not too hard to understand the purpose of functions, but you'll probably worry about how you can possibly memorize all the different functions out there. If you've ever used functions in a spreadsheet, such as the ROUND function which rounds a decimal number to the nearest integer, this chapter won't feel too alien to you. Transforming values in the ORDER BY clause. ![]() Transforming values in the WHERE clause.Basic definition and syntax of a function. ![]()
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