Linked Questions

Possible Duplicate: COUNT() vs. COUNT(1) vs. COUNT(pk): which is better? count() and count(column_name), what's the diff? count(*) vs count(column-name) - which is more correct? The ...

I'm trying to find out if a row exists in a table. Using MySQL, is it better to do a query like this: SELECT COUNT(*) AS total FROM table1 WHERE ... and check to see if the total is non-zero or is it ...

I have a record of students and I need to group them by age. I have this scenario: If Age group has only one member, display his/her name and sex Else Display 'SOME STRING' as name Check sex of ...

Q1: why count(*) is so much slower than count(distinct col)? Q2: should id always use count(distinct col)? select count(id) from source; +-----------+ | count(id) | +-----------+ | 22713 | +-----...

I'm trying to execute this query in a database through phpmyadmin create trigger avoid_duplicated_sharing before insert on sharingevents for each row begin if ( select count(*) from sharingevents ...

The table structure is as follows: Players (PlayerID, FirstName, LastName, PositionID) Salaries (SalaryID, PlayerID, Amount) ScoredGoals (GoalId, PlayerID, GameID, Minute) Positions (PositionID, ...

Consider the following table I need to return a list in descending order with the count of the member_nr's who is appearing the most frequent in the table where tournament = 'EPL' AND ROUND = '12' ...

Need to identify the most frequent occurrence of an item ID from an item description table, match it to its corresponding ID on an item sales table, and then display only the name from the description ...

I'm playing around with PHP. My issue is that my SELECT query with the COUNT() function is only returning one row, however when I query the database directly through phpmyadmin with what it echoes, ...

How do I find duplicate entries in a column (like multiple rows in student_id column) and join those to another table with common id (like student_id from another table to get student_name)? grades: ...

I have a pretty simple table like this: id | custom_id | answer ---------------------------------- 1 | 123 | Answer 1 __________________________________ 2 | 123 | ...

I'm using the following code snippet to select number of rows from students table. But it shows the error "Fatal error: Call to a member function bind_param() on a non-object". In my table 'stacyear' ...

I want to mysql query in a table that has 4 fields: id, user_one, user_two, hash. $check_con = mysql_query("SELECT count(hash) FROM messages_group WHERE (user_one=$my_id AND user_two=$other_id) OR ...