Query Syntax Reference

This document details the syntax of the Datui query language. For examples and typical workflows, see Querying Data.

Structure of a query

A query has the form:

select [columns] [by group_columns] [where conditions]

• select — Required. Starts every query. May be followed by nothing (select all columns), or a comma‑separated list of column expressions.
• by — Optional. Grouping and aggregation. Everything after by up to where (if present) is the group specification.
• where — Optional. Filtering. Everything after where is the filter expression.

Clause order is fixed: select → by → where. The parser splits on the keywords where and by (respecting parentheses and brackets), so you cannot reorder or repeat clauses.

The : assignment (aliasing)

Use : to name an expression. The form is name : expression:

• Left of : — The new column or group name. Must be an identifier (e.g. total) or col["name with spaces"].
• Right of : — The expression (column reference, literal, arithmetic, function call, etc.).

Examples:

select a, b, sum_ab: a + b
select renamed: col["Original Name"]
by region_name: region, total: sales + tax

Assignment is supported in both the select and by clauses. In by, it defines computed group keys or renames (e.g. region_name: region, total: sales + tax). Expressions may use column references, arithmetic, literals, and function calls.

Columns with spaces in their names

Identifiers cannot contain spaces. For columns (or aliases) with spaces, use col["..."] or col[identifier]:

select col["First Name"], col["Last Name"]
select no_spaces: col["name with spaces"]

Inside the brackets use either a quoted string ("name with spaces") or a single identifier (no spaces). The same syntax works in select, by, and where.

Right‑to‑left expression parsing

Expressions are parsed right‑to‑left: the leftmost binary operator is the root, and the right subexpression is parsed first (so it effectively binds tighter).

What this means

• a + b * c → parsed as a + (b * c) (multiplication binds tighter).
• a * b + c → parsed as a * (b + c) (* is leftmost; the right subexpression b + c is parsed as a unit).

So “higher‑precedence”‑style grouping happens when you put those operations on the right. You can often avoid parentheses by ordering:

select x, y: a * b + c    →  a * (b + c)
select x, y: a + b * c    →  a + (b * c)

Using parentheses

Use () to override grouping:

select (a + b) * c
select a, b where (x > 1) | (y < 0)

Parentheses also matter for , and | in where: splitting on comma and pipe respects nesting, so you can wrap ORs (or more complex logic) in () and then combine with commas. See Where clause: , and |.

Select clause

• select alone — All columns, no expressions.
• select a, b, c — Those columns (and/or expressions), in order.
• select a, b: x + y, c — Columns and aliased expressions.

Columns are separated by ,. Each item is either a plain expression or alias : expression. The same expression rules (arithmetic, col[], functions, etc.) apply everywhere.

By clause (grouping and aggregation)

• by col1, col2 — Group by those columns. Non‑group columns become list columns; the UI supports drill‑down.
• by region, total: sales + tax — Group by region and a computed expression (e.g. arithmetic).
• select avg salary, min id by department — Aggregations per group.

By uses the same comma‑separated list and name : expression rules as select. Aggregation functions (avg, min, max, count, sum, std, med) can be written as fn[expr] or fn expr (brackets optional).

Where clause: , and |

The where clause combines conditions using two separators:

• , — AND. Each comma‑separated segment is one ANDed condition.
• | — OR. Within a single comma‑separated segment, | separates alternatives that are ORed together.

Parsing order:

1. Split the where part on , (respecting () and []). Each segment is ANDed.
2. Within each segment, split on |. The pieces are ORed.

So:

• where a > 10, b < 2 → (a > 10) AND (b < 2).
• where a > 10 | a < 5 → (a > 10) OR (a < 5).
• where a > 10 | a < 5, b = 2 → (a > 10 OR a < 5) AND (b = 2).

Interaction of , and |

, has broader scope than |: it splits the where clause into top‑level AND terms. | only groups within one of those terms. So:

• A, B | C = A AND (B OR C).
• A | B, C | D = (A OR B) AND (C OR D).

To express (A or B) and (C or D), use (A)|(B), (C)|(D). Parentheses keep | inside each AND term. For more complex logic, use () to group OR subexpressions, then separate those groups with ,.

Comparison operators

In where conditions, each comparison operator compares a left-hand expression (often a column) to a right-hand expression (column, literal, or expression).

Operators and literals

• Arithmetic: + - * % ( % is division, not modulo).
• Comparison: See Comparison operators (where clauses) above.
• Literals: Numbers (42, 3.14), strings ("hello", \" for embedded quotes).

Functions

Functions are used for aggregation (typically in select with by) and for logic in where. Write fn[expr] or fn expr; brackets are optional.

Aggregation functions

Logic function

Summary