where

✅  select values based on a Boolean expression

Synopsis

[where] <expr> 

Description

The where operator filters its input by applying a Boolean expression <expr> to each input value and dropping each value for which the expression evaluates to false or to an error.

The where keyword is optional since it is a shortcut.

When SuperSQL queries are run interactively, it is highly convenient to be able to omit the “where” keyword, but when where filters appear in query source files, it is good practice to include the optional keyword.

Examples

An arithmetic comparison

# spq where this >= 2 # input 1 2 3 # expected output 2 3 

The “where” keyword may be dropped

# spq this >= 2 # input 1 2 3 # expected output 2 3 

A filter with Boolean logic

# spq where this >= 2 AND this <= 2 # input 1 2 3 # expected output 2 

A filter with array containment logic

# spq where this in [1,4] # input 1 2 3 4 # expected output 1 4 

A filter with inverse containment logic

# spq where ! (this in [1,4]) # input 1 2 3 4 # expected output 2 3 

Boolean functions may be called

# spq where has(a) # input {a:1} {b:"foo"} {a:10.0.0.1,b:"bar"} # expected output {a:1} {a:10.0.0.1,b:"bar"} 

Boolean functions with Boolean logic

# spq where has(a) or has(b) # input {a:1} {b:"foo"} {a:10.0.0.1,b:"bar"} # expected output {a:1} {b:"foo"} {a:10.0.0.1,b:"bar"}