openxs@ao756:~/dbs/maria10.2$ bin/mysql --host=127.0.0.1 --port=3308 -uroot testReading table information for completion of table and column names

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Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 8

Server version: 10.2.7-MariaDB Source distribution

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [test]> create table tt1(c1 int);

Query OK, 0 rows affected (0.31 sec)

MariaDB [test]> create table tt2(c2 int);

Query OK, 0 rows affected (0.22 sec)

MariaDB [test]> select count(*) from information_schema.columns where table_schema='test' and (table_name, column_name) in (('tt1', 'c1'));

+----------+

| count(*) |

+----------+

|        1 |

+----------+

1 row in set (0.04 sec)

MariaDB [test]> select count(*) from information_schema.columns where table_schema='test' and (table_name, column_name) in (('tt2', 'c2'));

+----------+

| count(*) |

+----------+

|        1 |

+----------+

1 row in set (0.00 sec)

MariaDB [test]> select count(*) from information_schema.columns where table_schema='test' and (table_name, column_name) in (('tt1','c1'),('tt2', 'c2'));

+----------+

| count(*) |

+----------+

|        0 |

+----------+

1 row in set (0.01 sec)

MariaDB [test]> select count(*) from information_schema.columns where table_schema='test' and (table_name, column_name) in (select 'tt1','c1' from dual union select 'tt2', 'c2' from dual);

+----------+

| count(*) |

+----------+

|        0 |

+----------+

1 row in set (0.02 sec)

MariaDB [test]> select count(*) from information_schema.columns where table_schema='test' and (table_name='tt1' and column_name='c1') or (table_name='tt2' and column_name='c2');

+----------+

| count(*) |

+----------+

|        2 |

+----------+

1 row in set (0.00 sec)