94f86eda79
* Some improvements for introduction/performance.md
* Minor improvements for example_datasets
* Add website/package-lock.json to .gitignore
* YT paragraph was badly outdated and there is no real reason to write a new one
* Use weird introduction article as a starting point for F.A.Q.
* Some refactoring of first half of ya_metrika_task.md
* minor
* Weird docs footer bugfix
* Forgotten redirect
* h/v scrollbars same size in docs
* CLICKHOUSE-3831: introduce security changelog
* A bit more narrow tables on docs front page
* fix flag in ru docs
* Save some space in top level of docs ToC
* Capitalize most words in titles of docs/en/
* more docs scrollbar fixes
* fix incorrect merge
* fix link
* fix switching languages in single page docs mode
* Update mkdocs & mkdocs-material + unminify javascript
* cherrypick 17e18d1ecc
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Operators
All operators are transformed to the corresponding functions at the query parsing stage, in accordance with their precedence and associativity. Groups of operators are listed in order of priority (the higher it is in the list, the earlier the operator is connected to its arguments).
Access Operators
a[N] Access to an element of an array; arrayElement(a, N) function.
a.N – Access to a tuble element; tupleElement(a, N) function.
Numeric Negation Operator
-a – The negate (a) function.
Multiplication and Division Operators
a * b – The multiply (a, b) function.
a / b – The divide(a, b) function.
a % b – The modulo(a, b) function.
Addition and Subtraction Operators
a + b – The plus(a, b) function.
a - b – The minus(a, b) function.
Comparison Operators
a = b – The equals(a, b) function.
a == b – The equals(a, b) function.
a != b – The notEquals(a, b) function.
a <> b – The notEquals(a, b) function.
a <= b – The lessOrEquals(a, b) function.
a >= b – The greaterOrEquals(a, b) function.
a < b – The less(a, b) function.
a > b – The greater(a, b) function.
a LIKE s – The like(a, b) function.
a NOT LIKE s – The notLike(a, b) function.
a BETWEEN b AND c – The same as a >= b AND a <= c.
Operators for Working With Data Sets
See the section "IN operators".
a IN ... – The in(a, b) function
a NOT IN ... – The notIn(a, b) function.
a GLOBAL IN ... – The globalIn(a, b) function.
a GLOBAL NOT IN ... – The globalNotIn(a, b) function.
Logical Negation Operator
NOT a The not(a) function.
Logical AND Operator
a AND b – Theand(a, b) function.
Logical OR Operator
a OR b – The or(a, b) function.
Conditional Operator
a ? b : c – The if(a, b, c) function.
Note:
The conditional operator calculates the values of b and c, then checks whether condition a is met, and then returns the corresponding value. If "b" or "c" is an arrayJoin() function, each row will be replicated regardless of the "a" condition.
Conditional Expression
CASE [x]
WHEN a THEN b
[WHEN ... THEN ...]
ELSE c
END
If "x" is specified, then transform(x, [a, ...], [b, ...], c). Otherwise – multiIf(a, b, ..., c).
Concatenation Operator
s1 || s2 – The concat(s1, s2) function.
Lambda Creation Operator
x -> expr – The lambda(x, expr) function.
The following operators do not have a priority, since they are brackets:
Array Creation Operator
[x1, ...] – The array(x1, ...) function.
Tuple Creation Operator
(x1, x2, ...) – The tuple(x2, x2, ...) function.
Associativity
All binary operators have left associativity. For example, 1 + 2 + 3 is transformed to plus(plus(1, 2), 3).
Sometimes this doesn't work the way you expect. For example, SELECT 4 > 2 > 3 will result in 0.
For efficiency, the and and or functions accept any number of arguments. The corresponding chains of AND and OR operators are transformed to a single call of these functions.