5.1 Functions and Operators

EventQL provides a large number of functions and operators for the built-in data types. Users can also define their own functions and operators.

Control Flow Functions

if an if statement with lazy evalutation if(1 == 2, "foo", "bar")

String Functions

REGEXP	REGEXP operator	`'foobar' REGEXP '^foo'`
endswith	check string end	`endswith("eventql", "ql")`
startswith	check string start	`startswith("eventql", "event")`
uppercase	convert to uppercase	`uppercase("hello world")`
ucase	alias for uppercase	`ucase("hello world")`
lowercase	convert to lowercase	`lowercase("hello world")`
lcase	alias for lowercase	`lcase("hello world")`
substring	Extract substring as specified.	`substring("foobar", 2, 3)`
substr	alias for substring	`substr("foobar", 3)`
concat	Add two strings.	`concat("event", "ql")`

Numeric Functions

+	Sum of two values	`2 + 2`
*	Multiply two numbers	`4 * 2`
/	Division operator	`4 / 2`
pow	Power operator	`pow(2, 32)`
round	Round a number	`round(0.234, 2)`
truncate	Truncate a number	`truncate(0.234, 2)`

Boolean Functions

!	Logical Negation operator	`!true`
==	'Equal' operator	`2 == 2`
!=	'Not equal' operator	`2 != 3`
<	'Less than' operator	`2 < 4`
<=	'Less or equal than' operator	`2 <= 4`
>	'Greather than' operator	`4 > 2`
>=	'Greather or equal than' operator	`4 >= 2`
AND	Logical and	`1 < 2 AND 2 < 3`
OR	Logical or	`1 < 2 OR 2 < 3`
isnull	Check if value is null	`isnull(null)`

DateTime Functions

from_timestamp	Convert a timestamp to a DateTime value	`from_timestamp(1462125626)`
date_trunc	Truncate to specified precision	`date_trunc("d", 1462125626)`
date_add	Add interval	`date_add(1462125626, '1', 'DAY')`
time_at	Get DateTime value for interval from now	`time_at('-12hours')`

Aggregate Functions

sum	Sum of all values in the result set	`sum(price)`
count	Number of values in the result set	`count(1)`
min	Minimum of values in the result set	`min(price)`
max	Maximum of values in the result set	`max(price)`
mean	mean of values in the result set	`mean(price)`

Conversion Functions

to_str	Convert to string	`to_str(1)`
to_int	Convert to integer	`to_int(142.23)`
to_float	Convert to float	`to_float(12)`
to_bool	Convert to string	`to_bool(1)`

Miscellaneous Functions

fnv32	Calculate a FNV32 hash.	`fnv32("test")`
usleep	Sleep for a number of microseconds	`usleep(1000)`

Operator Precedence

Operator precedences are shown in the following list, from highest precedence to the lowest. Operators that are shown together on a line have the same precedence.

!
- (unary minus), ~ (unary bit inversion)
^
*, /, DIV, %, MOD
-, +
<<, >>
&
|
= (comparison), <=>, >=, >, <=, <, <>, !=, IS, LIKE, REGEXP, IN
BETWEEN, CASE, WHEN, THEN, ELSE
NOT
&&, AND
XOR
||, OR