Revert "*: fix incorrect results when handling like with escape (p…

…ingcap#5431)"

This reverts commit 794bfe8.

dbms/src/Storages/Transaction/Collator.cpp

@@ -92,12 +92,15 @@ class Pattern : public ITiDBCollator::IPattern
                 tp = MatchType::Match;
                 if (offset < pattern.length())
                 {
-                    // use next char to match
-                    c = Collator::decodeChar(pattern.data(), offset);
-                }
-                else
-                {
-                    // use `escape` to match
+                    auto old_offset = offset;
+                    c = Collator::decodeChar(pattern.data(), old_offset);
+                    if (c == escape || c == '_' || c == '%')
+                        offset = old_offset;
+                    else
+                    {
+                        assert(escape >= 0);
+                        c = static_cast<decltype(c)>(escape); // NOLINT(bugprone-signed-char-misuse)
+                    }
                 }
             }
             else if (c == '_')

tests/fullstack-test/expr/like.test

@@ -38,29 +38,4 @@ mysql> set @@tidb_isolation_read_engines='tiflash'; select * from test.t where '
 | a    | b    |
 +------+------+
 | aaaa | %a%  |
-+------+------+
-
-mysql> insert into test.t values ('1234', '');
-
-mysql> set @@tidb_isolation_read_engines='tiflash'; select a from test.t where a like '1234' escape '4';
-+------+
-| a    |
-+------+
-| 1234 |
-+------+
-
-mysql> set @@tidb_isolation_read_engines='tiflash'; select a from test.t where a like '1234' escape '2';
-
-mysql> set @@tidb_isolation_read_engines='tiflash'; select a from test.t where a like '15234' escape '5';
-+------+
-| a    |
-+------+
-| 1234 |
-+------+
-
-mysql> set @@tidb_isolation_read_engines='tiflash'; select a from test.t where a like '_223_' escape '2';
-+------+
-| a    |
-+------+
-| 1234 |
-+------+
++------+------+