String Functions
Transform and inspect text values.
Questions this answers
- →How do I make text uppercase or lowercase?
- →How do I extract part of a string?
- →How do I join two strings together?
- →How do I find the length of a string?
- →How do I remove whitespace from a string?
How it works
SQL has a rich set of functions for working with text. The exact function names vary slightly between databases, but the concepts are universal: transform case, extract substrings, concatenate, measure length, and trim whitespace.
Case functions
SELECT UPPER(name) AS upper_name, LOWER(name) AS lower_name FROM artists;
Substring extraction
-- SUBSTR(string, start, length) SELECT SUBSTR(name, 1, 3) AS first_three FROM artists;
Concatenation
SELECT name || ' — ' || genre AS label FROM artists;
💡 Use || in SQLite/PostgreSQL. Use CONCAT() in MySQL.
Length and trim
SELECT LENGTH(name) AS name_length, TRIM(name) AS trimmed_name FROM artists;
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