EqualTo Predicate Expression¶

EqualTo is a BinaryComparison and NullIntolerant predicate expression that represents the following high-level operators in a logical plan:

• =, ==, <>, != SQL operators
• Column.===, Column.=!= and Column.notEqual operators

Creating Instance¶

EqualTo takes the following to be created:

• Left Expression
• Right Expression

EqualTo is created when:

• AstBuilder is requested to parse a comparison (for =, ==, <>, != operators) and visitSimpleCase
• Column.===, Column.=!= and Column.notEqual operators are used
• others

Symbol¶

symbol: String

symbol is part of the BinaryOperator abstraction.

symbol is = (equal sign).

Catalyst DSL¶

Catalyst DSL defines === operator to create an EqualTo expression.

import org.apache.spark.sql.catalyst.dsl.expressions._
val right = 'right
val left = 'left
val e = right === left

scala> e.explain(extended = true)
('right = 'left)

scala> println(e.expr.sql)
(`right` = `left`)

import org.apache.spark.sql.catalyst.expressions.EqualTo
assert(e.expr.isInstanceOf[EqualTo])