append_trailing_char_if_absent
description
Syntax
VARCHAR append_trailing_char_if_absent(VARCHAR str, VARCHAR trailing_char)
如果 str 字符串非空并且末尾不包含 trailing_char 字符，则将 trailing_char 字符附加到末尾。 trailing_char 只能包含一个字符，如果包含多个字符，将返回NULL
example
MySQL [test]> select append_trailing_char_if_absent('a','c');
+------------------------------------------+
| append_trailing_char_if_absent('a', 'c') |
+------------------------------------------+
| ac |
+------------------------------------------+
1 row in set (0.02 sec)
MySQL [test]> select append_trailing_char_if_absent('ac','c');
+-------------------------------------------+
| append_trailing_char_if_absent('ac', 'c') |
+-------------------------------------------+
| ac |
+-------------------------------------------+
1 row in set (0.00 sec)keywords
APPEND_TRAILING_CHAR_IF_ABSENT