updating-rows-in-a-table

Updating All Rows in a Table

An update statement for all rows:

UPDATE <table> SET <column> = <value>;

The = sign is different from an equality operator from a WHERE condition. It's an assignment operator because you're assigning a new value to something.

Examples:

UPDATE users SET password = "thisisabadidea";
UPDATE products SET price = 2.99;

Update multiple columns in all rows:

UDPATE <table> SET <column 1> = <value 1>, <column 2> = <value 2>;

Examples:

UPDATE users SET first_name = "Anony", last_name = "Moose";
UPDATE products SET stock_count = 0, price = 0;

Updating Specific Rows

An update statement for specific rows:

UPDATE <table> SET <column> = <value> WHERE <condition>;

Examples:

UPDATE users SET password = "thisisabadidea" WHERE id = 3;
UPDATE blog_posts SET view_count = 1923 WHERE title = "SQL is Awesome";

Update multiple columns for specific rows:

UDPATE <table> SET <column 1> = <value 1>, <column 2> = <value 2> WHERE <condition>;

Examples:

UPDATE users SET entry_url = "/home", last_login = "2016-01-05" WHERE id = 329;
UPDATE products SET status = "SOLD OUT", availability = "In 1 Week" WHERE stock_count = 0;

Removing Data from All Rows in a Table

To delete all rows from a table:

DELETE FROM <table>;

Examples:

DELETE FROM logs;
DELETE FROM users;
DELETE FROM products;