SUBSTRING(_string_, _start_, _length_) Character offset starts at 1
CAST(field_name AS newtype) Dealing with different datatypes
LEN(string) Length of a string
CONCAT('SQL', ' is', ' fun!') Two or more strings
CONTAINS (column_name, 'search_pattern')
DISTINCT Removes duplicates
EXISTS (subquery) Returns TRUE if the subquery returns at least one row, otherwise it returns FALSE
<> not equal to
BETWEEN between these two values
IS NULL and IS NOT NULL
SUM() Returns the total of all values.
AVG() Returns the mean average of all values.
COUNT() Counts and returns the number of values.
MIN() Returns the smallest value.
MAX() Returns the largest value.
GROUP BY in combination with HAVING
Returns only Matching Records
SELECT table.field FROM first_table INNER JOIN second_table ON first_table.field = second_table.field;INNER is the default join type for JOIN (you can just write JOIN)
WHERE column LIKE pattern
Percentage (% ) wildcard matches a sequence of any character including space
Underscore ( _ ) wildcard matches any single character
Default format is YYYY-MM-DD
YEAR Extracts year from a date
When using nested queries, the query inside parentheses runs first, and then its result is used in the outside query