1 files changed, 24 insertions, 1 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala
index 49b7797113..a36da8e94b 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala
@@ -69,7 +69,30 @@ abstract class StringRegexExpression extends BinaryExpression
  * Simple RegEx pattern matching function
  */
 @ExpressionDescription(
-  usage = "str _FUNC_ pattern - Returns true if `str` matches `pattern`, or false otherwise.")
+  usage = "str _FUNC_ pattern - Returns true if str matches pattern, " +
+    "null if any arguments are null, false otherwise.",
+  extended = """
+    Arguments:
+      str - a string expression
+      pattern - a string expression. The pattern is a string which is matched literally, with
+        exception to the following special symbols:
+
+          _ matches any one character in the input (similar to . in posix regular expressions)
+
+          % matches zero ore more characters in the input (similar to .* in posix regular
+          expressions)
+
+        The escape character is '\'. If an escape character precedes a special symbol or another
+        escape character, the following character is matched literally. It is invalid to escape
+        any other character.
+
+    Examples:
+      > SELECT '%SystemDrive%\Users\John' _FUNC_ '\%SystemDrive\%\\Users%'
+      true
+
+    See also:
+      Use RLIKE to match with standard regular expressions.
+""")
 case class Like(left: Expression, right: Expression) extends StringRegexExpression {
 
   override def escape(v: String): String = StringUtils.escapeLikeRegex(v)