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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 n ames WHERE Sname LIKE '%a'; USEFUL FUNCTIONS Get the count of characters in a string: SELECT. LENGTH('LearnSQL.com');-- result: 12 Convert all letters to lowercase: SELECT ...
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.
1 cze 2021 · function will return NULL if x is the same as y, else it will return the x value. CASE WHEN. The basic version of . CASE WHEN. checks if the values are equal (e.g., if fee is equal to 50, then 'normal' is returned). If there isn't a matching value in the CASE WHEN, then the ELSE value will be returned (e.g., if fee is equal to 49, then 'not
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 ...
22 paź 2024 · Regular practice helps you get better at using SQL and boosts your confidence in handling different database tasks. So, in this free SQL exercises page, we'll cover a series of SQL practice exercises covering a wide range of topics suitable for beginners, intermediate, and advanced SQL learners.
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.
FULL OUTER JOIN facts f ON f.id = c.facts_id; Joining tables using a FULL OUTER JOIN: SELECT name, migration_rate FROM FACTS ORDER BY 2 desc; -- 2 refers to migration_rate column Sorting a column without specifying a column name: SELECT c.name capital_city, f.name country FROM facts f INNER JOIN (SELECT * FROM cities WHERE capital = 1
