aggregate function

performs a calculation on a set of values and returns a single value.

MIN

the minimum attribute value encountered in a given column

MAX

the maximum attribute value encountered in a given column

COUNT

the number of rows containing non-null values

SUM

the sum of all values for a given column

AVG

the arithmetic mean (average) for a specified column

GROUP BY

command option is often used with aggregate functions to group the result-set by one or more columns.

alias

to assign a temporary name to the column. It can also be given to tables.

HAVING

command option is used to restrict the output of a GROUP BY query by applying conditional criteria to the grouped rows.

GETDATE

returns the current date and time

DATEADD

adds a number of selected time/date periods to a date then returns the date

DATEDIFF

returns the difference between two (2) dates

ABS

returns the absolute value of a number

ROUND

rounds a number to a specified number of decimal places

CEILING

returns the smallest integer value that is greater than or equal to a number

FLOOR

returns the largest integer value that is less than or equal to a number

CONCAT

joins two or more strings together

LOWER

returns a string in lowercase letters

UPPER

returns a string in all capital letters

SUBSTRING

returns a part of a string

LEN

returns the number of characters in a string

TRIM

removes the spaces or specific characters from start or end of a string

JOIN

combines rows from two or more tables based on a common column.

INNER JOIN

returns rows that have matching values in both tables

LEFT JOIN

returns all rows from the left table and the matched records from the right table. If there is no match from the right side, the result is NULL.

RIGHT JOIN

returns all rows from the right table and the matched records from the left table. If there is no match from the left side, the result is NULL.

FULL JOIN

returns all records when there is a match on either the left or right table. If there is no match, the missing side will contain NULL