Put the columns names explicitly rather than *, and make sure the number of columns and data types match for the same column in each select. Update: I really don’t think you want to be UNIONing those tables, based on the tables names. They don’t seem to contain related data. If you post your schema … Read more
In addition to this answer if you need to change tableB.value according to tableA.value dynamically you can do for example:
You can use IF() where in Oracle you would have used DECODE().
A Table can have a Composite Primary Key which is a primary key made from two or more columns. For example: Update: Here is a link with a more detailed description of composite primary keys.
They both represent floating point numbers. A FLOAT is for single-precision, while a DOUBLE is for double-precision numbers. MySQL uses four bytes for single-precision values and eight bytes for double-precision values. There is a big difference from floating point numbers and decimal (numeric) numbers, which you can use with the DECIMAL data type. This is … Read more
database user does not have the permission to do select query. you can grant the permission to the user if you have root access to mysql http://dev.mysql.com/doc/refman/5.1/en/grant.html Your second query is on different database on different table. And the user you are connecting with does not have permission to access data from this database or … Read more
If I do SHOW GRANTS in my mysql database I get If I am not mistaken, root@localhost means that user root can access the server only from localhost. How do I tell MySQL to grant root the permission to access this mysql server from every other machine (in the same network), too?
IMPORTANT: do NOT delete ibdata1 file. You could destroy all your databases. Instead, first try using the MySQL backup folder which is included with XAMPP. So do next steps: Rename folder mysql/data to mysql/data_old Make a copy of mysql/backup folder and name it as mysql/data Copy all your database folders from mysql/data_old into mysql/data (except … Read more
Try this OR
TL;DR: To access newer versions of mysql/mariadb as the root user, after a new install, you need to be in a root shell (ie sudo mysql -u root, or mysql -u root inside a shell started by su – or sudo -i first) Having just done the same upgrade, on Ubuntu, I had the same issue. What was odd was that Would accept … Read more