[MySQL uses (3)] Some errors encountered when using MySQL

1, Err1055, this problem occurs often in the execution of SQL statements, the last line will appear this problem.

[ERR] 1055-expression #1 of ORDER by clause are not in GROUP by clause and contains nonaggregated column ' Information_sch Ema. PROFILING. SEQ ' which is not functionally dependent on columns in GROUP by clause; This was incompatible with sql_mode=only_full_group_by

Workaround:

In the/etc/my.cnf file, add the following:
Sql_mode= ' No_engine_substitution '
Then, restarting the MySQL service will solve the problem!

2, ERROR2003, open the MySQL connection tool when this problem occurs

"ERROR 2003:can ' t connect to MySQL server on ' localhost ' (10061)"

Workaround:

This is due to the fact that the MySQL service did not start

2.1, if the installation version of MySQL, service items inside the start of the MySQL service can be.

2.2, compressed version of MySQL, under the DOS window into the MySQL file bin directory, knock the following command mysqld

Use the following command if you are not connected at this time

D:\develop tools\mysql Server 5.6\bin>mysql-u root-penter password:welcome to the MySQL Monitor.  Commands End With; or \g.your MySQL connection ID is 14Server version:5.6.24 mysql Community Server (GPL) Copyright (c) +, Oracle an d/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names trademarks of their respectiveowners. Type ' help ', ' or ' \h ' for help. Type ' \c ' to clear the current input statement.mysql>

3, ERR 1248 nested subqueries problem

[ERR] 1248-every derived table must has its own alias

Solution: This situation is generally due to the problem of nested subqueries, for MySQL nested subqueries must be aliased, otherwise it will error, there will be no such errors in Oracle!!!!

4. ERR 12,411 column corresponds to multi-value problem

[ERR] 1241-operand should contain 1 column (s)

Solution: This is usually the case because a field = multiple value problems, this time to use the In field can be solved.

[MySQL uses (3)] Some errors encountered when using MySQL