Sql Server equivalent of a COUNTIF aggregate function
You could use a SUM (not COUNT!) combined with a CASE statement, like this: Note: in my own test NULLs were not an issue, though this can be environment dependent. You could handle nulls such as:
Database
Mysql: Setup the format of DATETIME to ‘DD-MM-YYYY HH:MM:SS’ when creating a table
“MySQL retrieves and displays DATETIME values in ‘YYYY-MM-DD HH:MM:SS’ format.” This is from mysql site. You can store only this type, but you can use one of the many time format functions to change it, when you need to display it. Mysql Time and Date functions For example, one of those functions is the DATE_FORMAT, which … Read more
SQL not a single-group group function
Well the problem simply-put is that the SUM(TIME) for a specific SSN on your query is a single value, so it’s objecting to MAX as it makes no sense (The maximum of a single value is meaningless). Not sure what SQL database server you’re using but I suspect you want a query more like this … Read more
Update statement to update multiple rows
I have a question regarding the following syntax. Is there a cleaner way to roll this up into one statement rather than two. I’ve tried several iterations but this seems to be the only way I can successfully execute these two statements. I tried this as well and I also tried using an AND statement. … Read more
How do I limit the number of rows returned by an Oracle query after ordering?
Starting from Oracle 12c R1 (12.1), there is a row limiting clause. It does not use familiar LIMIT syntax, but it can do the job better with more options. You can find the full syntax here. (Also read more on how this works internally in Oracle in this answer). To answer the original question, here’s the query: (For earlier Oracle versions, please … Read more
SQL – Update multiple records in one query
Try either multi-table update syntax Here is SQLFiddle demo or conditional update Here is SQLFiddle demo
mysql Foreign key constraint is incorrectly formed error
I ran into this same problem with HeidiSQL. The error you receive is very cryptic. My problem ended up being that the foreign key column and the referencing column were not of the same type or length. The foreign key column was SMALLINT(5) UNSIGNED and the referenced column was INT(10) UNSIGNED. Once I made them both the same … Read more
Can’t connect to local MySQL server through socket ‘/tmp/mysql.sock’ (2)
I have installed MySQL server and trying to connect to it, but getting the error: I have checked my /tmp directory and there is no mysql.sock. I can’t find mysql.sock anywhere. I read that it might be in But I checked there as well and there is even no mysql directory, only some postfix thing … Read more
PHP Connection failed: SQLSTATE[HY000] [2002] Connection refused
I found the reason why the connection was not working, it was because the connection was trying to connect to port 8888, when it needed to connect to port 8889. This fixed the problem, although changing the server name to localhost still gives the error. Connection failed: SQLSTATE[HY000] [2002] No such file or directory But … Read more
MySQL: Access denied for user ‘test’@’localhost’ (using password: YES) except root user
I am facing problem with mysql non root/admin user, I am following the below steps for creating user and its privileges, correct me if i am doing wrong, i am installing mysql on RHEL 5.7 64bit, packages are mentioned below, once i done the rpm install we are creating mysql db using mysql_install_db, then starting the mysql service then using mysql_upgrade also we … Read more