Self Join to get employee manager name
EDIT: Left Join will work if emp_mgr_id is null.
Database
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
Conversion failed when converting date and/or time from character string while inserting datetime
There are many formats supported by SQL Server – see the MSDN Books Online on CAST and CONVERT. Most of those formats are dependent on what settings you have – therefore, these settings might work some times – and sometimes not. The way to solve this is to use the (slightly adapted) ISO-8601 date format … Read more
The wait operation timed out. ASP
If you found the exact error “The wait operation timed out” then it is likely you have a database call that took longer than expected. This could be due to any number of things: Transient network problem High SQL server load Problem with SAN, RAID, or storage device Deadlock or other form of multiprocess contention … Read more
What is SELF JOIN and when would you use it? [duplicate]
You use a self join when a table references data in itself. E.g., an Employee table may have a SupervisorID column that points to the employee that is the boss of the current employee. To query the data and get information for both people in one row, you could self join like this:
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
The wait operation timed out. ASP
If you found the exact error “The wait operation timed out” then it is likely you have a database call that took longer than expected. This could be due to any number of things: Transient network problem High SQL server load Problem with SAN, RAID, or storage device Deadlock or other form of multiprocess contention … Read more
SQL Inner-join with 3 tables?
You can do the following (I guessed on table fields,etc) Based on your request for multiple halls you could do it this way. You just join on your Hall table multiple times for each room pref id:
Column count doesn’t match value count at row 1
The error means that you are providing not as much data as the table wp_posts does contain columns. And now the DB engine does not know in which columns to put your data. To overcome this you must provide the names of the columns you want to fill. Example: Look up the table definition and see which … Read more