Module expr

Expand description

Type-safe SQL expression system.

This module provides a type-safe wrapper around SQL expressions that tracks:

The SQL data type of the expression
Whether the expression can be NULL
Whether the expression is an aggregate or scalar

§Example

use drizzle_core::expr::*;

// Type-safe comparisons
let condition = eq(users.id, 10);  // OK: Int == Int
// let bad = eq(users.id, "hello"); // ERROR: Int != Text

// Type-safe arithmetic
let total = users.price + users.tax;  // OK: both Numeric
// let bad = users.name + users.id;   // ERROR: Text + Int

Structs§

Agg: Marker indicating an aggregate expression (COUNT, SUM, etc.).
NonNull: Marker indicating an expression cannot be NULL.
Null: Marker indicating an expression can be NULL.
SQLExpr: A SQL expression that carries type information.
Scalar: Marker indicating a scalar (non-aggregate) expression.

Traits§

AggregateKind: Marker trait for expression aggregation state.
Expr: An expression in SQL with an associated data type.
ExprExt: Extension trait providing method-based comparisons for any Expr type.
NullOr: Combine nullability: if either input is nullable, output is nullable.
Nullability: Marker trait for nullability state.

Functions§

abs: ABS - returns the absolute value of a number.
age: AGE - calculates the interval between two timestamps (PostgreSQL).
alias: Create an aliased expression.
and: Logical AND of multiple conditions.
and2: Logical AND of two expressions.
avg: AVG(expr) - calculates average of numeric values.
avg_distinct: AVG(DISTINCT expr) - calculates average of distinct numeric values.
between: BETWEEN comparison.
cast: Cast an expression to a different type.
ceil: CEIL / CEILING - rounds a number up to the nearest integer.
coalesce: COALESCE - returns first non-null value.
coalesce_many: COALESCE with multiple values.
concat: Concatenate two string expressions using || operator.
count: COUNT(expr) - counts non-null values.
count_all: COUNT(*) - counts all rows.
count_distinct: COUNT(DISTINCT expr) - counts distinct non-null values.
current_date: CURRENT_DATE - returns the current date.
current_time: CURRENT_TIME - returns the current time.
current_timestamp: CURRENT_TIMESTAMP - returns the current timestamp.
date: DATE - extracts the date part from a temporal expression (SQLite).
date_trunc: DATE_TRUNC - truncates a timestamp to specified precision (PostgreSQL).
datetime: DATETIME - creates a datetime from a temporal expression (SQLite).
distinct: DISTINCT - marks an expression as DISTINCT.
eq: Equality comparison (=).
exists: EXISTS subquery check.
exp: EXP - returns e raised to the power of the argument.
extract: EXTRACT - extracts a component from a temporal expression (PostgreSQL/Standard SQL).
floor: FLOOR - rounds a number down to the nearest integer.
group_concat: GROUP_CONCAT / STRING_AGG - concatenates values into a string.
gt: Greater-than comparison (>).
gte: Greater-than-or-equal comparison (>=).
ifnull: IFNULL - SQLite/MySQL equivalent of COALESCE with two arguments.
in_array: IN array check.
in_subquery: IN subquery check.
instr: INSTR - finds the position of a substring.
is_not_null: IS NOT NULL check.
is_null: IS NULL check.
julianday: JULIANDAY - converts a temporal expression to Julian day number (SQLite).
length: LENGTH - returns the length of a string.
like: LIKE pattern matching.
ln: LN - returns the natural logarithm of a number.
log: LOG - returns the logarithm of a number with a specified base.
log10: LOG10 - returns the base-10 logarithm of a number.
lower: LOWER - converts string to lowercase.
lt: Less-than comparison (<).
lte: Less-than-or-equal comparison (<=).
ltrim: LTRIM - removes leading whitespace.
max: MAX(expr) - finds maximum value.
min: MIN(expr) - finds minimum value.
mod_: MOD - returns the remainder of division (using % operator).
neq: Inequality comparison (<> or !=).
not: Logical NOT.
not_between: NOT BETWEEN comparison.
not_exists: NOT EXISTS subquery check.
not_in_array: NOT IN array check.
not_in_subquery: NOT IN subquery check.
not_like: NOT LIKE pattern matching.
now: NOW - returns the current timestamp with time zone (PostgreSQL).
nullif: NULLIF - returns NULL if arguments are equal, else first argument.
or: Logical OR of multiple conditions.
or2: Logical OR of two expressions.
power: POWER - raises a number to a power.
raw: Create a raw SQL expression with a specified type.
raw_non_null: Create a raw SQL expression with explicit nullability.
replace: REPLACE - replaces occurrences of a substring.
round: ROUND - rounds a number to the nearest integer (or specified precision).
round_to: ROUND with precision - rounds a number to specified decimal places.
rtrim: RTRIM - removes trailing whitespace.
sign: SIGN - returns the sign of a number (-1, 0, or 1).
sqrt: SQRT - returns the square root of a number.
stddev_pop: STDDEV_POP - population standard deviation.
stddev_samp: STDDEV_SAMP / STDDEV - sample standard deviation.
strftime: STRFTIME - formats a temporal expression as text (SQLite).
string_concat: Concatenate two string expressions using || operator.
substr: SUBSTR - extracts a substring from a string.
sum: SUM(expr) - sums numeric values.
sum_distinct: SUM(DISTINCT expr) - sums distinct numeric values.
time: TIME - extracts the time part from a temporal expression (SQLite).
to_char: TO_CHAR - formats a temporal expression as text (PostgreSQL).
to_timestamp: TO_TIMESTAMP - converts a Unix timestamp to a timestamp (PostgreSQL).
trim: TRIM - removes leading and trailing whitespace.
trunc: TRUNC - truncates a number towards zero.
typeof: Alias for typeof_ (uses Rust raw identifier syntax).
typeof_: Get the SQL type of an expression.
unixepoch: UNIXEPOCH - converts a temporal expression to Unix timestamp (SQLite 3.38+).
upper: UPPER - converts string to uppercase.
var_pop: VAR_POP - population variance.
var_samp: VAR_SAMP / VARIANCE - sample variance.

Type Aliases§

AggExpr: An aggregate, non-null expression.
NullableAggExpr: An aggregate, nullable expression.
NullableExpr: A scalar, nullable expression.
ScalarExpr: A scalar, non-null expression.

Module expr

Module expr Copy item path

§Example

Structs§

Traits§

Functions§

Type Aliases§

Module expr