extended keyword for the explain statement has been removed

[yahonda]

This pull request addresses #893

$ bundle exec rspec ./spec/mysql2/client_spec.rb:328
Run options: include {:locations=>{"./spec/mysql2/client_spec.rb"=>[328]}}

Randomized with seed 11457

Mysql2::Client
  #warning_count
    when has a warnings
      should > 0 (FAILED - 1)

Failures:

  1) Mysql2::Client#warning_count when has a warnings should > 0
     Failure/Error: _query(sql, @query_options.merge(options))

     Mysql2::Error:
       You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select 1' at line 1
     # ./lib/mysql2/client.rb:120:in `_query'
     # ./lib/mysql2/client.rb:120:in `block in query'
     # ./lib/mysql2/client.rb:119:in `handle_interrupt'
     # ./lib/mysql2/client.rb:119:in `query'
     # ./spec/mysql2/client_spec.rb:331:in `block (4 levels) in <top (required)>'

Finished in 0.0126 seconds (files took 0.18505 seconds to load)
1 example, 1 failure

Failed examples:

rspec ./spec/mysql2/client_spec.rb:328 # Mysql2::Client#warning_count when has a warnings should > 0

Randomized with seed 11457

$

https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-3.html

The deprecated EXTENDED and PARTITIONS keywords for the EXPLAIN statement have been removed. These keywords are unnecessary because their effect is always enabled.

Use another select 1/0 which generates warnings:

mysql> select 1/0;
+------+
| 1/0  |
+------+
| NULL |
+------+
1 row in set, 1 warning (0.01 sec)

mysql> show warnings;
+---------+------+---------------+
| Level   | Code | Message       |
+---------+------+---------------+
| Warning | 1365 | Division by 0 |
+---------+------+---------------+
1 row in set (0.00 sec)

mysql>

[sodabrew]

Thank you for looking into this MySQL 8.0 issue! Unfortunately this does not generate a warning with MySQL < 8.0. Would an SELECT with a syntax error work?

[yahonda]

Use DROP TABLE IF EXISTS test.no_such_table explained in https://dev.mysql.com/doc/refman/5.7/en/show-warnings.html

mysql> DROP TABLE IF EXISTS test.no_such_table;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> SHOW WARNINGS;
+-------+------+------------------------------------+
| Level | Code | Message                            |
+-------+------+------------------------------------+
| Note  | 1051 | Unknown table 'test.no_such_table' |
+-------+------+------------------------------------+
1 row in set (0.00 sec)

mysql>

Would an SELECT with a syntax error work?

Attempted to useselect statement, which just returns ERROR , not like Query OK, 0 rows affected, 1 warning (0.00 sec). Then prefer to use drop table statement here.

mysql> select * from test.no_such_table;
ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist
mysql> SHOW WARNINGS;
+-------+------+------------------------------------------+
| Level | Code | Message                                  |
+-------+------+------------------------------------------+
| Error | 1146 | Table 'test.no_such_table' doesn't exist |
+-------+------+------------------------------------------+
1 row in set (0.00 sec)

mysql>