SELECT * FROM users WHERE name = 'Amir';SELECT email FROM users WHERE name = 'Amir';
Note that the standard equality operator in SQL is =
Most SQL databases support not-equal comparisons with the familiar != operator. Sometimes you’ll also see the <> operator, as in a <> b, which means the same thing.
AND and OR
length
SELECT name FROM users WHERE length(name) > 4
Different database systems provide different functions. SQLite only provides a few functions, but PostgreSQL provides hundreds. We can also define our own functions, then use them in queries.