Enum Expr 

pub enum Expr {
    Column {
        table: Option<String>,
        name: String,
    },
    Literal(Value),
    Placeholder(usize),
    Binary {
        left: Box<Expr>,
        op: BinaryOp,
        right: Box<Expr>,
    },
    Unary {
        op: UnaryOp,
        expr: Box<Expr>,
    },
    Function {
        name: String,
        args: Vec<Expr>,
    },
    Case {
        when_clauses: Vec<(Expr, Expr)>,
        else_clause: Option<Box<Expr>>,
    },
    In {
        expr: Box<Expr>,
        values: Vec<Expr>,
        negated: bool,
    },
    Between {
        expr: Box<Expr>,
        low: Box<Expr>,
        high: Box<Expr>,
        negated: bool,
    },
    IsNull {
        expr: Box<Expr>,
        negated: bool,
    },
    IsDistinctFrom {
        left: Box<Expr>,
        right: Box<Expr>,
        negated: bool,
    },
    Cast {
        expr: Box<Expr>,
        type_name: String,
    },
    Like {
        expr: Box<Expr>,
        pattern: String,
        negated: bool,
        case_insensitive: bool,
    },
    Subquery(String),
    Exists {
        subquery: String,
        params: Vec<Value>,
        negated: bool,
    },
    Raw(String),
    Paren(Box<Expr>),
    CountStar,
    Window {
        function: Box<Expr>,
        partition_by: Vec<Expr>,
        order_by: Vec<OrderBy>,
        frame: Option<WindowFrame>,
    },
    JsonExtract {
        expr: Box<Expr>,
        path: JsonPath,
    },
    JsonExtractText {
        expr: Box<Expr>,
        path: JsonPath,
    },
    JsonExtractPath {
        expr: Box<Expr>,
        path: Vec<String>,
    },
    JsonExtractPathText {
        expr: Box<Expr>,
        path: Vec<String>,
    },
    JsonContains {
        expr: Box<Expr>,
        other: Box<Expr>,
    },
    JsonContainedBy {
        expr: Box<Expr>,
        other: Box<Expr>,
    },
    JsonHasKey {
        expr: Box<Expr>,
        key: String,
    },
    JsonHasAnyKey {
        expr: Box<Expr>,
        keys: Vec<String>,
    },
    JsonHasAllKeys {
        expr: Box<Expr>,
        keys: Vec<String>,
    },
    JsonArrayLength {
        expr: Box<Expr>,
    },
    JsonTypeof {
        expr: Box<Expr>,
    },
}

A SQL expression that can be used in WHERE, HAVING, etc.

Variants

Column

Column reference with optional table qualifier

Fields

table: Option<String>

Optional table name or alias

name: String

Column name

Literal(Value)

Literal value

Placeholder(usize)

Explicit placeholder for bound parameters

Binary

Binary operation (e.g., a = b, a > b)

Fields

left: Box<Expr>

op: BinaryOp

right: Box<Expr>

Unary

Unary operation (e.g., NOT a, -a)

Fields

op: UnaryOp

expr: Box<Expr>

Function

Function call (e.g., COUNT(*), UPPER(name))

Fields

name: String

args: Vec<Expr>

Case

CASE WHEN … THEN … ELSE … END

Fields

when_clauses: Vec<(Expr, Expr)>

List of (condition, result) pairs

else_clause: Option<Box<Expr>>

Optional ELSE clause

In

IN expression

Fields

expr: Box<Expr>

values: Vec<Expr>

negated: bool

Between

BETWEEN expression

Fields

expr: Box<Expr>

low: Box<Expr>

high: Box<Expr>

negated: bool

IsNull

IS NULL / IS NOT NULL

Fields

expr: Box<Expr>

negated: bool

IsDistinctFrom

IS DISTINCT FROM / IS NOT DISTINCT FROM (NULL-safe comparison)

Fields

left: Box<Expr>

right: Box<Expr>

negated: bool

Cast

CAST(expr AS type)

Fields

expr: Box<Expr>

type_name: String

Like

LIKE / NOT LIKE pattern

Fields

expr: Box<Expr>

pattern: String

negated: bool

case_insensitive: bool

Subquery(String)

Subquery (stores the SQL string)

Exists

EXISTS (subquery) / NOT EXISTS (subquery)

Used for subquery existence checks in WHERE clauses.

Fields

subquery: String

The subquery SQL string

params: Vec<Value>

Parameters for the subquery

negated: bool

Whether this is NOT EXISTS

Raw(String)

Raw SQL fragment (escape hatch)

Paren(Box<Expr>)

Parenthesized expression

CountStar

Special aggregate: COUNT(*)

Window

Window function with OVER clause

Fields

function: Box<Expr>

The function expression (aggregate or window function)

partition_by: Vec<Expr>

PARTITION BY expressions

order_by: Vec<OrderBy>

ORDER BY clauses within the window

frame: Option<WindowFrame>

Frame specification (ROWS or RANGE)

JsonExtract

JSON path extraction (returns JSON value)

• PostgreSQL: expr -> 'path' or expr -> path_expr
• MySQL: JSON_EXTRACT(expr, '$.path')
• SQLite: json_extract(expr, '$.path')

Fields

expr: Box<Expr>

The JSON expression to extract from

path: JsonPath

The path to extract (can be a key name or array index)

JsonExtractText

JSON path extraction as text (returns text/string)

• PostgreSQL: expr ->> 'path'
• MySQL: JSON_UNQUOTE(JSON_EXTRACT(expr, '$.path'))
• SQLite: json_extract(expr, '$.path') (SQLite returns text by default)

Fields

expr: Box<Expr>

The JSON expression to extract from

path: JsonPath

The path to extract

JsonExtractPath

JSON path extraction with nested path (returns JSON)

• PostgreSQL: expr #> '{path, to, value}'
• MySQL/SQLite: JSON_EXTRACT(expr, '$.path.to.value')

Fields

expr: Box<Expr>

The JSON expression

path: Vec<String>

Nested path segments

JsonExtractPathText

JSON path extraction with nested path as text

• PostgreSQL: expr #>> '{path, to, value}'
• MySQL: JSON_UNQUOTE(JSON_EXTRACT(expr, '$.path.to.value'))
• SQLite: json_extract(expr, '$.path.to.value')

Fields

expr: Box<Expr>

The JSON expression

path: Vec<String>

Nested path segments

JsonContains

JSON containment check (left contains right)

• PostgreSQL: expr @> other (JSONB only)
• MySQL: JSON_CONTAINS(expr, other)
• SQLite: Not directly supported (requires json_each workaround)

Fields

expr: Box<Expr>

The JSON expression to check

other: Box<Expr>

The JSON value to check for

JsonContainedBy

JSON contained-by check (left is contained by right)

• PostgreSQL: expr <@ other (JSONB only)
• MySQL: JSON_CONTAINS(other, expr)
• SQLite: Not directly supported

Fields

expr: Box<Expr>

The JSON expression to check

other: Box<Expr>

The containing JSON value

JsonHasKey

JSON key existence check

• PostgreSQL: expr ? 'key' (JSONB only)
• MySQL: JSON_CONTAINS_PATH(expr, 'one', '$.key')
• SQLite: json_type(expr, '$.key') IS NOT NULL

Fields

expr: Box<Expr>

The JSON expression

key: String

The key to check for

JsonHasAnyKey

JSON any key existence (has any of the keys)

• PostgreSQL: expr ?| array['key1', 'key2'] (JSONB only)
• MySQL: JSON_CONTAINS_PATH(expr, 'one', '$.key1', '$.key2')
• SQLite: Requires OR of json_type checks

Fields

expr: Box<Expr>

The JSON expression

keys: Vec<String>

The keys to check for

JsonHasAllKeys

JSON all keys existence (has all of the keys)

• PostgreSQL: expr ?& array['key1', 'key2'] (JSONB only)
• MySQL: JSON_CONTAINS_PATH(expr, 'all', '$.key1', '$.key2')
• SQLite: Requires AND of json_type checks

Fields

expr: Box<Expr>

The JSON expression

keys: Vec<String>

The keys to check for

JsonArrayLength

JSON array length

• PostgreSQL: jsonb_array_length(expr)
• MySQL: JSON_LENGTH(expr)
• SQLite: json_array_length(expr)

Fields

expr: Box<Expr>

The JSON array expression

JsonTypeof

JSON typeof (returns the type of the JSON value)

• PostgreSQL: jsonb_typeof(expr)
• MySQL: JSON_TYPE(expr)
• SQLite: json_type(expr)

Fields

expr: Box<Expr>

The JSON expression

Implementations

impl Expr

pub fn col(name: impl Into<String>) -> Self

Create a column reference expression.

pub fn qualified(table: impl Into<String>, column: impl Into<String>) -> Self

Create a qualified column reference (table.column).

pub fn lit(value: impl Into<Value>) -> Self

Create a literal value expression.

pub fn null() -> Self

Create a NULL literal.

pub fn raw(sql: impl Into<String>) -> Self

Create a raw SQL expression (escape hatch).

pub fn placeholder(index: usize) -> Self

Create a placeholder for bound parameters.

pub fn eq(self, other: impl Into<Expr>) -> Self

Equal to (=)

pub fn ne(self, other: impl Into<Expr>) -> Self

Not equal to (<>)

pub fn lt(self, other: impl Into<Expr>) -> Self

Less than (<)

pub fn le(self, other: impl Into<Expr>) -> Self

Less than or equal to (<=)

pub fn gt(self, other: impl Into<Expr>) -> Self

Greater than (>)

pub fn ge(self, other: impl Into<Expr>) -> Self

Greater than or equal to (>=)

pub fn and(self, other: impl Into<Expr>) -> Self

Logical AND

pub fn or(self, other: impl Into<Expr>) -> Self

Logical OR

pub fn not(self) -> Self

Logical NOT

pub fn is_null(self) -> Self

IS NULL

pub fn is_not_null(self) -> Self

IS NOT NULL

pub fn is_distinct_from(self, other: impl Into<Expr>) -> Self

IS DISTINCT FROM (NULL-safe comparison: returns TRUE/FALSE, never NULL)

Unlike !=, this returns TRUE when comparing NULL to a non-NULL value, and FALSE when comparing NULL to NULL.

pub fn is_not_distinct_from(self, other: impl Into<Expr>) -> Self

IS NOT DISTINCT FROM (NULL-safe equality: returns TRUE/FALSE, never NULL)

Unlike =, this returns TRUE when comparing NULL to NULL, and FALSE when comparing NULL to a non-NULL value.

pub fn cast(self, type_name: impl Into<String>) -> Self

CAST expression to a specific SQL type.

Example

Expr::col("price").cast("DECIMAL(10, 2)")
// Generates: CAST("price" AS DECIMAL(10, 2))

pub fn like(self, pattern: impl Into<String>) -> Self

LIKE pattern match

pub fn not_like(self, pattern: impl Into<String>) -> Self

NOT LIKE pattern match

pub fn ilike(self, pattern: impl Into<String>) -> Self

ILIKE (case-insensitive) pattern match (PostgreSQL)

pub fn not_ilike(self, pattern: impl Into<String>) -> Self

NOT ILIKE pattern match (PostgreSQL)

pub fn contains(self, pattern: impl AsRef<str>) -> Self

Check if column contains the given substring (LIKE ‘%pattern%’).

Example

Expr::col("name").contains("man")
// Generates: "name" LIKE '%man%'

pub fn starts_with(self, pattern: impl AsRef<str>) -> Self

Check if column starts with the given prefix (LIKE ‘pattern%’).

Example

Expr::col("name").starts_with("Spider")
// Generates: "name" LIKE 'Spider%'

pub fn ends_with(self, pattern: impl AsRef<str>) -> Self

Check if column ends with the given suffix (LIKE ‘%pattern’).

Example

Expr::col("name").ends_with("man")
// Generates: "name" LIKE '%man'

pub fn icontains(self, pattern: impl AsRef<str>) -> Self

Case-insensitive contains (ILIKE ‘%pattern%’ or LOWER fallback).

pub fn istarts_with(self, pattern: impl AsRef<str>) -> Self

Case-insensitive starts_with (ILIKE ‘pattern%’ or LOWER fallback).

pub fn iends_with(self, pattern: impl AsRef<str>) -> Self

Case-insensitive ends_with (ILIKE ‘%pattern’ or LOWER fallback).

pub fn in_list(self, values: Vec<impl Into<Expr>>) -> Self

IN list of values

pub fn not_in_list(self, values: Vec<impl Into<Expr>>) -> Self

NOT IN list of values

pub fn between(self, low: impl Into<Expr>, high: impl Into<Expr>) -> Self

BETWEEN low AND high

pub fn not_between(self, low: impl Into<Expr>, high: impl Into<Expr>) -> Self

NOT BETWEEN low AND high

pub fn add(self, other: impl Into<Expr>) -> Self

Addition (+)

pub fn sub(self, other: impl Into<Expr>) -> Self

Subtraction (-)

pub fn mul(self, other: impl Into<Expr>) -> Self

Multiplication (*)

pub fn div(self, other: impl Into<Expr>) -> Self

Division (/)

pub fn modulo(self, other: impl Into<Expr>) -> Self

Modulo (%)

pub fn neg(self) -> Self

Negation (unary -)

pub fn concat(self, other: impl Into<Expr>) -> Self

String concatenation (||)

pub fn array_contains(self, other: impl Into<Expr>) -> Self

Array contains (@>). Tests if this array contains all elements of other.

pub fn array_contained_by(self, other: impl Into<Expr>) -> Self

Array contained by (<@). Tests if this array is contained by other.

pub fn array_overlap(self, other: impl Into<Expr>) -> Self

Array overlap (&&). Tests if this array has any elements in common with other.

pub fn array_any_eq(self, value: impl Into<Expr>) -> Self

ANY(array) = value. Tests if any element of the array equals the value.

Generates: value = ANY(array_column)

pub fn bit_and(self, other: impl Into<Expr>) -> Self

Bitwise AND (&)

pub fn bit_or(self, other: impl Into<Expr>) -> Self

Bitwise OR (|)

pub fn bit_xor(self, other: impl Into<Expr>) -> Self

Bitwise XOR (^)

pub fn bit_not(self) -> Self

Bitwise NOT (~)

pub fn case() -> CaseBuilder

Start building a CASE expression.

Example

Expr::case()
    .when(Expr::col("status").eq("active"), "Yes")
    .when(Expr::col("status").eq("pending"), "Maybe")
    .otherwise("No")

pub fn count_star() -> Self

COUNT(*) aggregate function.

pub fn count(self) -> Self

COUNT(expr) aggregate function.

pub fn sum(self) -> Self

SUM(expr) aggregate function.

pub fn avg(self) -> Self

AVG(expr) aggregate function.

pub fn min(self) -> Self

MIN(expr) aggregate function.

pub fn max(self) -> Self

MAX(expr) aggregate function.

pub fn function(name: impl Into<String>, args: Vec<Expr>) -> Self

Create a generic function call.

pub fn row_number() -> Self

ROW_NUMBER() window function. Returns the sequential number of a row within a partition.

pub fn rank() -> Self

RANK() window function. Returns the rank of the current row with gaps.

pub fn dense_rank() -> Self

DENSE_RANK() window function. Returns the rank of the current row without gaps.

pub fn percent_rank() -> Self

PERCENT_RANK() window function. Returns the relative rank of the current row.

pub fn cume_dist() -> Self

CUME_DIST() window function. Returns the cumulative distribution of a value.

pub fn ntile(n: i64) -> Self

NTILE(n) window function. Divides rows into n groups and returns the group number.

pub fn lag(self) -> Self

LAG(expr) window function with default offset of 1. Returns the value of expr from the row that precedes the current row.

pub fn lag_offset(self, offset: i64) -> Self

LAG(expr, offset) window function. Returns the value of expr from the row at the given offset before current row.

pub fn lag_with_default(self, offset: i64, default: impl Into<Expr>) -> Self

LAG(expr, offset, default) window function. Returns the value of expr or default if the offset row doesn’t exist.

pub fn lead(self) -> Self

LEAD(expr) window function with default offset of 1. Returns the value of expr from the row that follows the current row.

pub fn lead_offset(self, offset: i64) -> Self

LEAD(expr, offset) window function. Returns the value of expr from the row at the given offset after current row.

pub fn lead_with_default(self, offset: i64, default: impl Into<Expr>) -> Self

LEAD(expr, offset, default) window function. Returns the value of expr or default if the offset row doesn’t exist.

pub fn first_value(self) -> Self

FIRST_VALUE(expr) window function. Returns the first value within the window frame.

pub fn last_value(self) -> Self

LAST_VALUE(expr) window function. Returns the last value within the window frame.

pub fn nth_value(self, n: i64) -> Self

NTH_VALUE(expr, n) window function. Returns the nth value within the window frame.

pub fn over(self) -> WindowBuilder

Start building a window function with OVER clause.

Example

// ROW_NUMBER() OVER (PARTITION BY department ORDER BY salary DESC)
Expr::row_number()
    .over()
    .partition_by(Expr::col("department"))
    .order_by(Expr::col("salary").desc())
    .build()

// SUM(amount) OVER (PARTITION BY customer_id)
Expr::col("amount").sum()
    .over()
    .partition_by(Expr::col("customer_id"))
    .build()

pub fn coalesce(args: Vec<impl Into<Expr>>) -> Self

COALESCE function: returns the first non-NULL argument.

Example

Expr::coalesce(vec![Expr::col("nickname"), Expr::col("name"), Expr::lit("Anonymous")])
// Generates: COALESCE("nickname", "name", 'Anonymous')

pub fn nullif(expr1: impl Into<Expr>, expr2: impl Into<Expr>) -> Self

NULLIF function: returns NULL if both arguments are equal, otherwise returns the first.

Example

Expr::nullif(Expr::col("value"), Expr::lit(0))
// Generates: NULLIF("value", 0)

pub fn ifnull(expr1: impl Into<Expr>, expr2: impl Into<Expr>) -> Self

IFNULL/NVL function (dialect-specific): returns expr2 if expr1 is NULL.

This generates IFNULL for SQLite/MySQL or COALESCE for PostgreSQL.

pub fn upper(self) -> Self

UPPER function: converts string to uppercase.

pub fn lower(self) -> Self

LOWER function: converts string to lowercase.

pub fn length(self) -> Self

LENGTH function: returns the length of a string.

pub fn trim(self) -> Self

TRIM function: removes leading and trailing whitespace.

pub fn ltrim(self) -> Self

LTRIM function: removes leading whitespace.

pub fn rtrim(self) -> Self

RTRIM function: removes trailing whitespace.

pub fn substr( self, start: impl Into<Expr>, length: Option<impl Into<Expr>>, ) -> Self

SUBSTR/SUBSTRING function: extracts a substring.

Arguments

• start - 1-based start position
• length - Optional length of substring

pub fn replace(self, from: impl Into<Expr>, to: impl Into<Expr>) -> Self

REPLACE function: replaces occurrences of a substring.

pub fn abs(self) -> Self

ABS function: returns absolute value.

pub fn round(self, decimals: impl Into<Expr>) -> Self

ROUND function: rounds to specified decimal places.

pub fn floor(self) -> Self

FLOOR function: rounds down to nearest integer.

pub fn ceil(self) -> Self

CEIL/CEILING function: rounds up to nearest integer.

pub fn asc(self) -> OrderBy

Create an ascending ORDER BY expression.

pub fn desc(self) -> OrderBy

Create a descending ORDER BY expression.

pub fn paren(self) -> Self

Wrap expression in parentheses.

pub fn subquery(sql: impl Into<String>) -> Self

Create a subquery expression.

pub fn exists(subquery_sql: impl Into<String>, params: Vec<Value>) -> Self

Create an EXISTS subquery expression.

Arguments

• subquery_sql - The SELECT subquery SQL (without outer parentheses)
• params - Parameters for the subquery

Example

// EXISTS (SELECT 1 FROM orders WHERE orders.customer_id = customers.id)
Expr::exists(
    "SELECT 1 FROM orders WHERE orders.customer_id = customers.id",
    vec![]
)

pub fn not_exists(subquery_sql: impl Into<String>, params: Vec<Value>) -> Self

Create a NOT EXISTS subquery expression.

Arguments

• subquery_sql - The SELECT subquery SQL (without outer parentheses)
• params - Parameters for the subquery

Example

// NOT EXISTS (SELECT 1 FROM orders WHERE orders.customer_id = customers.id)
Expr::not_exists(
    "SELECT 1 FROM orders WHERE orders.customer_id = customers.id",
    vec![]
)

pub fn json_get(self, key: impl Into<String>) -> Self

Extract a JSON value by key (returns JSON).

Generates dialect-specific SQL:

• PostgreSQL: expr -> 'key'
• MySQL: JSON_EXTRACT(expr, '$.key')
• SQLite: json_extract(expr, '$.key')

Example

Expr::col("data").json_get("name")
// PostgreSQL: "data" -> 'name'
// MySQL: JSON_EXTRACT("data", '$.name')

pub fn json_get_index(self, index: i64) -> Self

Extract a JSON value by array index (returns JSON).

Generates dialect-specific SQL:

• PostgreSQL: expr -> 0
• MySQL: JSON_EXTRACT(expr, '$[0]')
• SQLite: json_extract(expr, '$[0]')

Example

Expr::col("items").json_get_index(0)
// PostgreSQL: "items" -> 0

pub fn json_get_text(self, key: impl Into<String>) -> Self

Extract a JSON value as text by key.

Generates dialect-specific SQL:

• PostgreSQL: expr ->> 'key'
• MySQL: JSON_UNQUOTE(JSON_EXTRACT(expr, '$.key'))
• SQLite: json_extract(expr, '$.key') (returns text)

Example

Expr::col("data").json_get_text("name")
// PostgreSQL: "data" ->> 'name'

pub fn json_get_text_index(self, index: i64) -> Self

Extract a JSON value as text by array index.

Example

Expr::col("items").json_get_text_index(0)
// PostgreSQL: "items" ->> 0

pub fn json_path(self, path: &[&str]) -> Self

Extract a nested JSON value by path (returns JSON).

Generates dialect-specific SQL:

• PostgreSQL: expr #> '{path, to, value}'
• MySQL: JSON_EXTRACT(expr, '$.path.to.value')
• SQLite: json_extract(expr, '$.path.to.value')

Example

Expr::col("data").json_path(&["address", "city"])
// PostgreSQL: "data" #> '{address, city}'

pub fn json_path_text(self, path: &[&str]) -> Self

Extract a nested JSON value by path as text.

Generates dialect-specific SQL:

• PostgreSQL: expr #>> '{path, to, value}'
• MySQL: JSON_UNQUOTE(JSON_EXTRACT(expr, '$.path.to.value'))
• SQLite: json_extract(expr, '$.path.to.value')

Example

Expr::col("data").json_path_text(&["address", "city"])
// PostgreSQL: "data" #>> '{address, city}'

pub fn json_contains(self, other: impl Into<Expr>) -> Self

Check if JSON contains another JSON value.

Generates dialect-specific SQL:

• PostgreSQL: expr @> other (JSONB only)
• MySQL: JSON_CONTAINS(expr, other)

Example

Expr::col("tags").json_contains(Expr::lit(r#"["rust"]"#))
// PostgreSQL: "tags" @> '["rust"]'

pub fn json_contained_by(self, other: impl Into<Expr>) -> Self

Check if JSON is contained by another JSON value.

Generates dialect-specific SQL:

• PostgreSQL: expr <@ other (JSONB only)
• MySQL: JSON_CONTAINS(other, expr)

Example

Expr::col("tags").json_contained_by(Expr::lit(r#"["rust", "python", "go"]"#))

pub fn json_has_key(self, key: impl Into<String>) -> Self

Check if JSON object has a specific key.

Generates dialect-specific SQL:

• PostgreSQL: expr ? 'key' (JSONB only)
• MySQL: JSON_CONTAINS_PATH(expr, 'one', '$.key')
• SQLite: json_type(expr, '$.key') IS NOT NULL

Example

Expr::col("data").json_has_key("email")
// PostgreSQL: "data" ? 'email'

pub fn json_has_any_key(self, keys: &[&str]) -> Self

Check if JSON object has any of the specified keys.

Generates dialect-specific SQL:

• PostgreSQL: expr ?| array['key1', 'key2'] (JSONB only)
• MySQL: JSON_CONTAINS_PATH(expr, 'one', '$.key1', '$.key2')

Example

Expr::col("data").json_has_any_key(&["email", "phone"])
// PostgreSQL: "data" ?| array['email', 'phone']

pub fn json_has_all_keys(self, keys: &[&str]) -> Self

Check if JSON object has all of the specified keys.

Generates dialect-specific SQL:

• PostgreSQL: expr ?& array['key1', 'key2'] (JSONB only)
• MySQL: JSON_CONTAINS_PATH(expr, 'all', '$.key1', '$.key2')

Example

Expr::col("data").json_has_all_keys(&["email", "phone"])
// PostgreSQL: "data" ?& array['email', 'phone']

pub fn json_array_length(self) -> Self

Get the length of a JSON array.

Generates dialect-specific SQL:

• PostgreSQL: jsonb_array_length(expr)
• MySQL: JSON_LENGTH(expr)
• SQLite: json_array_length(expr)

Example

Expr::col("items").json_array_length()

pub fn json_typeof(self) -> Self

Get the type of a JSON value.

Generates dialect-specific SQL:

• PostgreSQL: jsonb_typeof(expr)
• MySQL: JSON_TYPE(expr)
• SQLite: json_type(expr)

Example

Expr::col("data").json_typeof()

pub fn build(&self, params: &mut Vec<Value>, offset: usize) -> String

Build SQL string and collect parameters (default PostgreSQL dialect).

pub fn build_with_dialect( &self, dialect: Dialect, params: &mut Vec<Value>, offset: usize, ) -> String

Build SQL string with specific dialect.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Expr

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<&str> for Expr

fn from(s: &str) -> Self

Converts to this type from the input type.

impl From<String> for Expr

fn from(s: String) -> Self

Converts to this type from the input type.

impl From<Value> for Expr

fn from(v: Value) -> Self

Converts to this type from the input type.

impl From<bool> for Expr

fn from(b: bool) -> Self

Converts to this type from the input type.

impl From<f32> for Expr

fn from(n: f32) -> Self

Converts to this type from the input type.

impl From<f64> for Expr

fn from(n: f64) -> Self

Converts to this type from the input type.

impl From<i32> for Expr

fn from(n: i32) -> Self

Converts to this type from the input type.

impl From<i64> for Expr

fn from(n: i64) -> Self

Converts to this type from the input type.