SQL queries - 2

Return the a hundred books starting from 25th SELECT book_title FROM books LIMIT 25, 100 The first number in LIMIT is the offset, the second is the number.
I am retrieving 10 results at a time, but I like to know how many rows there’re total. SELECT SQL_CALC_FOUND_ROWS page_title FROM web_pages LIMIT 1,10; SELECT FOUND_ROWS(); The second query will tell you how many results there’re total, so you can display a phrase "Found 13,450,600 results, displaying 1-10". Note that FOUND_ROWS does not pay attention to the LIMITs you specified and always returns the total number of rows affected by query.
Select all teams that won either 2, 4, 6 or 8 games SELECT team_name FROM teams WHERE team_won IN (2, 4, 6, 8 );
Select all the users, whose phone number is null SELECT user_name FROM users WHERE ISNULL(phonenumber); SELECT user_name FROM users WHERE phonenumber IS NULL;
If the value in the column is repeatable, Find out the unique values ? Use DISTINCT in the query, such as SELECT DISTINCT user_firstname FROM users; SELECT COUNT (DISTINCT user_firstname) FROM users;
Find out which auto increment was assigned on the last insert SELECT LAST_INSERT_ID() will return the last value assigned by the auto_increment function. Note that you don’t have to specify the table name.
Delete the most recently posted question in the table questions DELETE FROM questions ORDER BY timestamp LIMIT 1
See all indexes defined for a table SHOW INDEX FROM questions
Change a column from VARCHAR(10) to VARCHAR(50) ALTER TABLE questions CHANGE content content VARCHAR(50)
Delete a column ALTER TABLE answers DROP answer_id
Find out all databases starting with ‘tech’ to which I have access to SHOW DATABASES LIKE ‘tech%’;
Get a portion of a string while fetching data SELECT SUBSTR(title, 1, 10) FROM questions;
Convert a string to UTF-8 while fetching data SELECT (question USING utf8);
What do % and _ mean inside LIKE statement ? % corresponds to 0 or more characters while  _ is exactly one character.
Get the month from a timestamp while fetching data SELECT MONTH(add_date) FROM questions;
Changing date format of a timestamp while fetching data SELECT DATE_FORMAT(add_date, ‘%Y-%m-%d’) FROM questions; A similar TIME_FORMAT function deals with time.
Add three minutes to a date while fetching data SELECT ADDDATE(add_date, INTERVAL 3 MINUTE) FROM questions;
Find 2nd highest salary in random database salary of employer SELECT salary FROM employee ORDER BY salary DESC LIMIT 1,1
Find three highest salary SELECT salary FROM employee ORDER BY salary DESC LIMIT 3