Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/18228#discussion_r126601977
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
---
@@ -1199,6 +1199,82 @@ case class Substring(str: Expression, pos:
Expression, len: Expression)
}
/**
+ * Returns the rightmost n characters from the string.
+ */
+@ExpressionDescription(
+ usage = "_FUNC_(str, len) - Returns the rightmost `len` characters from
the string `str`.",
+ extended = """
+ Examples:
+ > SELECT _FUNC_('Spark SQL', 3);
+ SQL
+ """)
+case class Right(str: Expression, len: Expression)
+ extends BinaryExpression with ImplicitCastInputTypes with NullIntolerant
{
--- End diff --
ok so we should do: `If(LessThanOrEqual(len, Literal(0),
Literal(UTF8String.EMPTY_UTF8), Substring(str, UnaryMinus(len)))`. Complex
expression is OK, after codegen, it should be almost same as a customize
implementation.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
