mysql Thu Mar  3 13:50:06 2011 > pager sed 's/,/ /g'
PAGER set to 'sed 's/,/ /g''
mysql Thu Mar  3 13:50:32 2011 > select group_concat(concat('drop database ',SCHEMA_NAME,';')) from information_schema.schemata where SCHEMA_NAME !='mysql' and SCHEMA_NAME !='information_schema';
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| group_concat(concat('drop database ' SCHEMA_NAME ';'))                                                                                                                                                  |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| drop database abc; drop database def; drop database ghi; drop database jkl; drop database mno; drop database pqr; drop database stu; drop database vwx; drop database yz; |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql Thu Mar  3 13:50:34 2011 > drop database abc; drop database def; drop database ghi; drop database jkl; drop database mno; drop database pqr; drop database stu; drop database vwx; drop database yz;
Query OK, 42 rows affected (2.37 sec)

Query OK, 101 rows affected (4.25 sec)

Query OK, 3 rows affected (0.09 sec)

Query OK, 2 rows affected (0.09 sec)

Query OK, 26 rows affected (0.72 sec)

Query OK, 2 rows affected (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

Query OK, 3 rows affected (0.12 sec)

Query OK, 160 rows affected (7.98 sec)

mysql Thu Mar  3 13:50:55 2011 > nopager
PAGER set to stdout
mysql Thu Mar  3 13:51:02 2011 >

Say you were trying to run a query which returned a heap of warnings and you want to go through the list ….

mysql> load data infile '/aaa/bbb/ccc' into table xyz LINES TERMINATED BY '\r\n';
Query OK, 0 rows affected, 65535 warnings (4 min 25.12 sec)

mysql> show warnings;
+---------+------+------------------------------------------------+
| Level   | Code | Message                                        |
+---------+------+------------------------------------------------+
| Warning | 1366 | Incorrect value: '' for column 'xx' at row 1   |
...
| Warning | 1366 | Incorrect value: '' for column 'xx' at row 9   |
| Warning | 1366 | Incorrect value: '' for column 'xx' at row 10  |
+---------+------+------------------------------------------------+
64 rows in set (0.00 sec)

As per above only 64 rows are show. Why?

mysql> show variables like 'max_error_count';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_error_count | 64    |
+-----------------+-------+
1 row in set (0.00 sec)

Ok so … what is the solution?

mysql> set max_error_count=65535;
Query OK, 0 rows affected (0.00 sec)

mysql> pager more
PAGER set to 'more'

Here I am setting the max_error_count to a high value only for the session and not globally.

Details here

The “pager more” will work only on *nix systems where the output will be “piped” to the `more` command on your OS and displayed in batches so you can pause the scrolling of the long output.

Having said the above, from my experience, when you have that many warnings, it’ll be a repetition of the same error or group of errors.