SQL DML Data Manipulation Language

SELECT
SELECT *
FROM someTable
ORDER BY pk_id;

VARIABLES 
SELECT id, machine, user
FROM db.tableA varA
JOIN db.tableB varB ON (varA.user = varB.user)
WHERE id=500
ORDER BY id
LIMIT 10;

/*! so db.tableA can be referenced by varA and db.tableB by varB */ 

INSERT INTO
INSERT INTO 〈table name〉( 〈column 1〉, 〈column 2〉,... 〈column n〉 )
VALUES ( 〈value 〉, 〈value 2〉, ..., 〈value n〉);
Note column names do not require quotation marks, however values do.

INSERT INTO 〈table name〉
VALUES
      ( 〈value 〉, 〈value 2〉, ..., 〈value n〉)
      ( 〈value 〉, 〈value 2〉, ..., 〈value n〉)
      ( 〈value 〉, 〈value 2〉, ..., 〈value n〉); 
Note: We can omit the column names so long as the list of values match the number of columns AND are in the correct order.

UPDATE WHERE
UPDATE 〈table_name〉
SET column1 = value1, column2 = value2, ...
WHERE 〈condition〉;

DELETE FROM
DELETE FROM 〈table_name〉 WHERE 〈condition〉;
DELETE FROM table_name
Note: the latter command removes ALL data from the table. 

If we wish to list all different values in a column and count the number of instances of that value.
SELECT "names", COUNT("names") AS numberOfTimes
FROM mydf
GROUP BY "names"
ORDER BY numberOfTimes;