Is it possible to conditionally select columns in MySQL?

I work on large database (hundreds of GB) and Mysql now gives me more or less satisfaction. I hesitate to cassandra on launch.  What I want to know everything before, so this kind of DBMS NoSQL is supposed to be faster than MySQL?  Several points: The...

Hello, I have a jQuery autocomplete "search" input. So you can type in something and it will suggest you results from a MySQL database. Now I have two tables in that database; table 'aliases' with columns 'alias', 'steamid', 'timesused' and...

I need some help with the mySQL SORT statement for listing reviews by how helpful they were rated by users. I have two columns in the review table: helpfulrate and totalrate. helpfulrate contains the number of people that rated the review helpful and...

select count(1), domain_id as "row_count", "domain_id" from rtr_traffic_mo group by domain_id; I gave the above query in mysql but instead of two columns its showing 3 columns. I basically want count(1) to be represented as row_count...

So, let's say my table on my table has four columns, 1, 2, 3, and 4 The table itself is 4 pages long BUT each column on each page of the pdf is also split into sun columns. Ex. Page one of my table looks like this: Column 1 (Sub columns A B C D), Column...

In MySQL, I want to select emails, firstname, date, etc from past orders where the email is unique. I then want to show other fields for that same row with the first match (the oldest) in the database. For example: Example Real Data: ID, Email, Name...

I am making a 'Richest Person List' on my Website. This is the Code: <div class="box2"> <p class="chat">Richest Person of the Month!</p> <br></br> <?php // Make a MySQL Connection $host = "CENSORED...

from here: http://dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html I find this example: CREATE TABLE animals ( grp ENUM('fish','mammal','bird') NOT NULL, id MEDIUMINT NOT NULL AUTO_INCREMENT, name CHAR(30) NOT NULL, PRIMARY KEY (grp,id) )...

If I issue a SELECT in mysql like: SELECT c1 FROM t1; and if c1 is indexed using a B-Tree index, then will my output essentially be equivalent to: SELECT c1 FROM t1 ORDER BY c1; Are there conditions for this to happen?