$()

Returns the value of a query parameter.

Syntax

$(EXPR, [DEFAULT_EXPR])

Required Parameter

EXPR
Expression that returns a query parameter name.

Optional Parameter

DEFAULT_EXPR
Expression or value that specifies the default return value of the function when EXPR is null.

Description

A query parameter is a variable that can be called in a query or a procedure. You can declare query parameters using the set or evalc query commands. Using a query parameter is useful when dynamically assigning values to a query and executing it; a query or procedure can reference a value of a query parameter by using the $() function.

Usage

  1. Retrieve data recorded in the YOUR_TABLE table for the last 7 days from the current time.

    set from=ago("7d")
    | set to=str(now())
    | table from=$("from") to=$("to") YOUR_TABLE
    
  2. Retrieve data recorded in the YOUR_TABLE table for the period specified by the query parameters _from and _to. If the query parameters have no value (null), retrieve data for the last 1 day from the current time.

    table from=$("_from", ago("1d")) to=$("_to", now()) YOUR_TABLE