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* Additional .gitignore entries * Merge a bunch of small articles about system tables into single one * Merge a bunch of small articles about formats into single one * Adapt table with formats to English docs too * Add SPb meetup link to main page * Move Utilities out of top level of docs (the location is probably not yet final) + translate couple articles * Merge MacOS.md into build_osx.md * Move Data types higher in ToC * Publish changelog on website alongside documentation * Few fixes for en/table_engines/file.md * Use smaller header sizes in changelogs * Group up table engines inside ToC * Move table engines out of top level too * Specificy in ToC that query language is SQL based. Thats a bit excessive, but catches eye. * Move stuff that is part of query language into respective folder * Move table functions lower in ToC * Lost redirects.txt update * Do not rely on comments in yaml + fix few ru titles * Extract major parts of queries.md into separate articles * queries.md has been supposed to be removed * Fix weird translation * Fix a bunch of links * There is only table of contents left * "Query language" is actually part of SQL abbreviation * Change filename in README.md too * fix mistype
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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.