Access denied for user ‘root@localhost’ (using password:NO)
You can reset your root password. Have in mind that it is not advisable to use root without password.
MySQL
How to use MySQL DECIMAL?
I can’t quite get a grasp of MySQL’s DECIMAL. I need the row to be able to contain a number anywhere from 00.0001 to 99.9999. How would I structure it to work like so?
MySQL Error “Operand should contain 1 column”
2 This question already has answers here: Operand Should Contain 1 Column – MySQL NOT IN (3 answers) Closed 7 years ago. I could find a lot of similar questions but no real solution for my problem. My SQL query: The error code I receive is If I just use the query in the parentheses … Read more
Cannot add or update a child row: a foreign key constraint fails
You’re getting this error because you’re trying to add/update a row to table2 that does not have a valid value for the UserID field based on the values currently stored in table1. If you post some more code I can help you diagnose the specific cause.
What’s the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN? [duplicate]
Reading this original article on The Code Project will help you a lot: Visual Representation of SQL Joins. Also check this post: SQL SERVER – Better Performance – LEFT JOIN or NOT IN?. Find original one at: Difference between JOIN and OUTER JOIN in MySQL.
String concatenation in MySQL
I am using MySQL and MySQL Workbench 5.2 CE. When I try to concatenate 2 columns, last_name and first_name, it doesn’t work :
ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)
Note: For MySQL 5.7+, please see the answer from Lahiru to this question. That contains more current information. For MySQL < 5.7: The default root password is blank (i.e., an empty string), not root. So you can just log in as: You should obviously change your root password after installation: In most cases you should … Read more
Cannot add or update a child row: a foreign key constraint fails
table #1: Field Type Null Key Default Extra UserID int(11) NO PRI NULL auto_increment Password varchar(20) NO Username varchar(25) NO Email varchar(60) NO table #2: Field Type Null Key Default Extra UserID int(11) NO MUL PostID int(11) NO PRI NULL auto_increment Title varchar(50) NO Summary varchar(500) NO Error: com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child … Read more
MySQL string replace
Now rows that were like http://www.example.com/articles/updates/43 will be
ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)
Note: For MySQL 5.7+, please see the [answer from Lahiru] to this question. That contains more current information. For MySQL < 5.7: The default root password is blank (i.e., an empty string), not root. So you can just log in as: You should obviously change your root password after installation: In most cases you should … Read more