Revert "add regex pattern to identify IN as a Compasion token"

This reverts commit 28c4d4026e1d9389a99d8cd627c96fa360c17fc4.

See #694. The expectation is that IN is primarily recognized as a keyword,
although it acts as a comparison operator. This also matches the definition of
IN in most SQL syntax references where it is listed as a reserved
keyword (PostgreSQL:
https://www.postgresql.org/docs/current/sql-keywords-appendix.html, MySQL:
https://dev.mysql.com/doc/refman/8.0/en/keywords.html, for example).

2 files changed, 2 insertions, 12 deletions

diff --git a/sqlparse/keywords.py b/sqlparse/keywords.py
index d73e114..dff5e1c 100644
--- a/sqlparse/keywords.py
+++ b/sqlparse/keywords.py
@@ -50,7 +50,7 @@ SQL_REGEX = {
         (r'(?<!\w)[$:?]\w+', tokens.Name.Placeholder),
 
         (r'\\\w+', tokens.Command),
-        (r'(NOT\s+)?(IN)\b', tokens.Operator.Comparison),
+
         # FIXME(andi): VALUES shouldn't be listed here
         # see https://github.com/andialbrecht/sqlparse/pull/64
         # AS and IN are special, it may be followed by a parenthesis, but
diff --git a/tests/test_grouping.py b/tests/test_grouping.py
index 546ad4b..03d16c5 100644
--- a/tests/test_grouping.py
+++ b/tests/test_grouping.py
@@ -376,20 +376,10 @@ def test_grouping_function_not_in():
     # issue183
     p = sqlparse.parse('in(1, 2)')[0]
     assert len(p.tokens) == 2
-    assert p.tokens[0].ttype == T.Comparison
+    assert p.tokens[0].ttype == T.Keyword
     assert isinstance(p.tokens[1], sql.Parenthesis)
 
 
-def test_in_comparison():
-    # issue566
-    p = sqlparse.parse('a in (1, 2)')[0]
-    assert len(p.tokens) == 1
-    assert isinstance(p.tokens[0], sql.Comparison)
-    assert len(p.tokens[0].tokens) == 5
-    assert p.tokens[0].left.value == 'a'
-    assert p.tokens[0].right.value == '(1, 2)'
-
-
 def test_grouping_varchar():
     p = sqlparse.parse('"text" Varchar(50) NOT NULL')[0]
     assert isinstance(p.tokens[2], sql.Function)