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1 cze 2021 · Fetch all names that start with any letter followed by 'atherine': SELECT name FROM names WHERE name LIKE '_atherine'; Fetch all names that end with 'a': SELECT name FROM names WHERE name LIKE '%a'; USEFUL FUNCTIONS. Get the count of characters in a string: SELECT LENGTH('LearnSQL.com');-- result: 12 Convert all letters to lowercase: SELECT ...
1 cze 2021 · Use the || operator to concatenate two strings: SELECT 'Hi ' || 'there!'; -- result: Hi there! ||. Use this trick for numbers: Some databases implement non-standard solutions for concatenating strings like CONCAT() or CONCAT_WS(). Check the documentation for your specific database. Use the _ character to replace any single character.
This edition of SQL Practice Problems assumes that you have some basic background knowledge about relational databases and tables. However, I’ve added some beginner level questions to gradually introduce the various parts of the SQL Select statement for those with less experience in SQL.
2 wrz 2024 · This SQL cheat sheet provide a wide range of commands and techniques essential for effective database management and data manipulation. By familiarizing yourself with these SQL operations, you can streamline your workflow, optimize performance and ensure data integrity across your database.
It starts from the absolute basics (SELECT * FROM table_name;) and guides you to the intermediate level (JOIN, HAVING, subqueries). I added everything that you will need as a data analyst/ scientist.
22 paź 2024 · This SQL quiz covers various topics like SQL basics, CRUD operations, operators, aggregation functions, constraints, joins, indexes, transactions, and query-based scenarios. We've included multiple-choice questions, fill-in-the-blank questions, and interactive coding challenges to keep things intere
SQL Cheat Sheet In this guide, you’ll find a useful cheat sheet that documents some of the more commonly used elements of SQL, and even a few of the less common. Hopefully, it will help developers – both beginner and experienced level – become more proficient in their understanding of the SQL language.
