….cur,const” with “ref” access type. At the stage when Join happens the value for third keypart is not yet avaiable… would return without subselect: mysql> select count(*) from Statement T join CurrDailyVal Q on Q.cur1 = T.cur and Q.cur2… sec) This subquery will need to be executed 55mi times so do not expect fast answer even if subquery is almost instant…
Comment: MySQL Limitations Part 3: Subqueries
October 25, 2010 By 21 Comments
Does this limitation on subqueries also affect subqueries that are used in JOIN clauses? For instance SELECT a.* FORM a JOIN (SELECT b.a_id FROM b WHERE b.blah = ‘asdf’)
Comment: When the subselect runs faster
April 19, 2010 By 9 Comments
Nikolay: If you would give me the explain I could give an exact answer. Now it’s looks like because the joins are slow/slower in the subquery. As I mentioned in the post, the subquery will be executed for each result of the main query. So in this case each query like this means 20 joins 
Comment: Air traffic queries in InfiniDB: early alpha
November 3, 2009 By 19 Comments
… the lack of subquery support, I agree with you on the need. We decided to implement hash joins in the engine first (which are in) and then come back to do subqueries that perform much…/resources/tech-articles/120-infinidb-community-edition-roadmap, which has subqueries coming out in alpha/beta around mid Q1 next year…
Post: Extended EXPLAIN
July 24, 2006 By 9 Comments
… `id`,`test`.`t2`.`pad` AS `pad` from `test`.`sbtest` `t1` join `test`.`sbtest` `t2` where ((`test`.`t2`.`k` = `test`.`t1`.`k… | NULL | NULL | NULL | NULL | 1000109 | Using where | | 2 | DEPENDENT SUBQUERY | sbtest | unique_subquery | PRIMARY | PRIMARY | 4 | func | 1 | Using index; Using where…
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
… levels of reduction of the set, all in parallel. All joins, aggregation and filtering is done at the storage node level… are documented in this blog post. This allows BETWEEN, IN, subqueries in the FROM clause, and UNION operations to operate fully…), sum(DepDelay), sum(DepDelay >= 0) flight_delayed from ontime_fact join dim_date on ontime_fact.date_id = dim_date.date…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… 100 of queries in this case. > This most applies to subqueries Where Subselects with IN() become > corellated even if they are… because it allows the optimizer to use the indexes to join rows together, potentially preventing a table scan. The trick is… of rows are scanned and returned. SELECT * FROM articles INNER JOIN users ON users.id = articles.user_id AND users.featured…
Comment: MySQL - to use or not to use
May 29, 2007 By 10 Comments
… with Subqueries being an exception, but most people I know who needed subqueries just didn’t know how to do proper joins 
Mostly…
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…) value55, left(var56.variable_value,40) var56 from var55 left join var56 on var55.variable_name=var56.variable_name where var55…-5.6.10-linux-glibc2. | | MAX_ALLOWED_PACKET | 1048576 | 4194304 | | JOIN_BUFFER_SIZE | 131072 | 262144 | | TMPDIR | /mnt/data/sandboxes/msb_5…_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on 1 row…
Comment: MySQL Limitations Part 3: Subqueries
October 25, 2010 By 21 Comments
One interesting point on the subqueries: Yes, I would dearly like to see this fixed as … times you are better off with a join, but not every case converts into join semantics easily or precisely and, frankly, a… logically correct inner select than will get a logically correct join.
