mysql-variables

Post the problem statement and current code I am using, and wondering if any smart ideas to improve query performance? Using MySQL. Thanks. Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a tie, the next ranking number should be the next consecutive integer value. In other words, there should be no "holes" between ranks. +----+-------+ | Id | Score | +----+-------+ | 1 | 3.50 | | 2 | 3.65 | | 3 | 4.00 | | 4 | 3.85 | | 5 | 4.00 | | 6 | 3.65 | +----+-------+ For example, given the above Scores table, your query should

I have a stored procedure that I am trying to call from my php. Here is the stored procedure: BEGIN DECLARE done INT DEFAULT FALSE; declare phone_temp VARCHAR(20) default ''; declare phone_cur cursor for SELECT DISTINCT sentNum FROM Queue; declare continue handler for not found set done = true; #create temp table create temporary table if not exists temp_return AS SELECT * FROM Queue LIMIT 0; #empty if exists delete from temp_return; open phone_cur; phone_loop: LOOP fetch phone_cur into phone_temp; if done then leave phone_loop; end if; insert into temp_return SELECT * FROM Queue WHERE num2

I've searched around for this, but all the similar questions and answers are just different enough not to work. I have a table with the following fields: person, thing, purdate. A new record is entered when a person buys each new thing. I want to count the consecutive months that a person bought any "thing" (thing01 or thing02, it doesn't mater). If there is a break in consecutive purdays, then the count should start over. With the data enclosed, I want to end up with this: | Person | Consec Days | | person_01 | 3 | | person_02 | 3 | | person_02 | 2 | I know I can get a distinct list of person

I would like to combine conditions from 2 different columns for my query. This is my original query. You can test it in sqlfiddle.com. -- creating database first for test data create table attendance(Id int, DateTime datetime, Door char(20)); INSERT INTO attendance VALUES ( 1, '2016-01-01 08:00:00', 'In'), ( 2, '2016-01-01 09:00:00', 'Out'), ( 3, '2016-01-01 09:15:00', 'In'), ( 4, '2016-01-01 09:30:00', 'In'), ( 5, '2016-01-01 10:00:00', 'Out'), ( 6, '2016-01-01 15:00:00', 'In'); SELECT * FROM attendance; SELECT @id:=@id+1 Id, MAX(IF(Door = 'In', DateTime, NULL)) `Check In`, MAX(IF(Door = 'Out

Is there a possibility to do something like this? SELECT @z:=SUM(item), 2*@z FROM TableA; I always get NULL for the second column. The strange thing is, that while doing something like SELECT @z:=someProcedure(item), 2*@z FROM TableA; everything works as expected. Why? MySQL documentation is quite clear on this: As a general rule, you should never assign a value to a user variable and read the value within the same statement. You might get the results you expect, but this is not guaranteed. The order of evaluation for expressions involving user variables is undefined and may change based on