Optimize php mySQL query with mulitple joins and Group_Concat -

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i have multiple join sets happening on query. have multiple joins, because of way tables structured want. main joins, i've separated 3 sets commented below. if have 1 set, query time pretty fast. when have 2 sets active, query time around 2 minutes. if 3 sets active shown below, takes long.

any on optimizing query appreciated.

$query  = "select   `databases`.*,                      `databasedescriptors`.*,                      `databasecontents`.*,                      `databaseaccesslevels`.*,                      `providers`.*,                      group_concat(`descriptors`.descriptorname separator ', ') descriptornames,                      group_concat(`contents`.contentname separator ', ') contentnames,                      group_concat(`accesslevels`.accesslevelname separator ', ') accesslevelnames ";  $query .= "from `databases` ";  // set 1  $query .= "join `databasedescriptors`                  on `databasedescriptors`.databaseid = `databases`.databaseid ";  $query .= "join `descriptors`                  on `descriptors`.descriptorid = `databasedescriptors`.descriptorid ";  //set 2  $query .= "join `databasecontents`                 on `databasecontents`.databaseid = `databases`.databaseid ";  $query .= "join `contents`                 on `contents`.contentid = `databasecontents`.contentid ";  //set 3  $query .= "join `databaseaccesslevels`                 on `databaseaccesslevels`.databaseid = `databases`.databaseid ";  $query .= "join `accesslevels`                 on `accesslevels`.accesslevelid = `databaseaccesslevels`.accesslevelid ";  $query .= "join `providers`                 on `providers`.providerid = `databases`.providerid ";  $query .= "and `databases`.databaseid = 47";

the reason performance problem "database" has multiple descriptors, access levels, , contents. database has 10 of each. query ends turning 10*10*10 = 1000 rows processing.

the solution aggregation before doing join. instance, instead of this: $query .= "join databasedescriptors on databasedescriptors.databaseid = databases.databaseid ";

$query .= "join `descriptors`                  on `descriptors`.descriptorid = `databasedescriptors`.descriptorid ";

you have:

(select dd.databaseid,          group_concat(d.descriptorname separator ', ') descriptornames  databasedescriptors dd join       descriptions d       on dd.descriptorid = d.descriptorid  group dd.databaseid ) dd on databases.databaseid = dd.databaseid

(you can replace group dd.databaseid where dd.databaseid = 47 handle 1 case. guess might want information databases. if so, add group databaseid outer query.)

you need repeat 3 of group_concat() columns.

note: pulling fields tables. however, 1 row returning because have aggregation query no group by. i'm guessing getting duplicates in group_concat()-created lists. approach fix problem.


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