换行和回车

MySQL version：8.0.18-commercial MySQL Enterprise Server - Commercial

正常查询GTID 是一间比较麻烦的事情
查询结果如下：

mysql> select @@gtid_purged,@@gtid_executed;
+------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
| @@gtid_purged                                                                                                                                  | @@gtid_executed |
+------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
| 5e4a0caf-75f9-11e9-9b95-fa163ec02d40:1-1005397,
660e027b-265b-11e8-92e9-fa163ee86ec3:1-893898218,
9310c9c3-2035-11e8-af8e-fa163e3facf6:1-16617 |                 |
+------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
1 row in set, 1 warning (0.00 sec)

去除换行和回车后：

mysql> select replace(@@gtid_purged,char(10),''),@@gtid_executed;
+----------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
| replace(@@gtid_purged,char(10),'')                                                                                                           | @@gtid_executed |
+----------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
| 5e4a0caf-75f9-11e9-9b95-fa163ec02d40:1-1005397,660e027b-265b-11e8-92e9-fa163ee86ec3:1-893898218,9310c9c3-2035-11e8-af8e-fa163e3facf6:1-16617 |                 |
+----------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
1 row in set, 1 warning (0.02 sec)

mysql> select replace(replace(@@gtid_purged,char(10),''),char(13),''),@@gtid_executed;
+----------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
| replace(replace(@@gtid_purged,char(10),''),char(13),'')                                                                                      | @@gtid_executed |
+----------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
| 5e4a0caf-75f9-11e9-9b95-fa163ec02d40:1-1005397,660e027b-265b-11e8-92e9-fa163ee86ec3:1-893898218,9310c9c3-2035-11e8-af8e-fa163e3facf6:1-16617 |                 |
+----------------------------------------------------------------------------------------------------------------------------------------------+-----------------+
1 row in set, 1 warning (0.00 sec)

这样看起来就很爽了。。有木有
正常情况下char(10)是换行键，char(13)是回车键

测试如下：

换行：
mysql> select concat('A',char(10),'B');
+--------------------------+
| concat('A',char(10),'B') |
+--------------------------+
| A
B                      |
+--------------------------+
1 row in set (0.03 sec)
回车：
mysql> select concat('A',char(13),'B');
+--------------------------+
| concat('A',char(13),'B') |
+--------------------------+
B                      |
+--------------------------+
1 row in set (0.00 sec)
咦.....A不见了.....
查看下length
mysql> select length('A');
+-------------+
| length('A') |
+-------------+
|           1 |
+-------------+
1 row in set (0.01 sec)

mysql> select length(concat('A',char(13)));
+------------------------------+
| length(concat('A',char(13))) |
+------------------------------+
|                            2 |
+------------------------------+
1 row in set (0.00 sec)
其中char(13)的length 是1，`length(concat('A',char(13)))` 应该是有结果的
mysql> select length(concat(char(13)));
+--------------------------+
| length(concat(char(13))) |
+--------------------------+
|                        1 |
+--------------------------+
1 row in set (0.00 sec)