mysql - SubQuery on Single Table -



mysql - SubQuery on Single Table -

ok have table

tasks -- taskid (unique autoinc primary) childof (contains task id of parent, or 0 if top tier (no parent))

i need write query selects records childof = 0 ... simple right ?

ok need have column returned results tells how many children each task has ...

so result ...

taskid ... childof ... countchildren 37 ...... 0 .... 3 42 ...... 0 .... 0 99 ...... 0 .... 1 etc....

i know 2 queries need this, need combine them somehow...

select taskid parenttaskid, childof tasks childof = 0

and

select count(taskid) tasks childof = parenttaskid

note: there 2 tiers.. parent , kid ... no grandchildren! makes bit less complicated.

any help appreciated. help far!

something should it:

select taskid parenttaskid, childof , (select count(t2.taskid) tasks t2 t2.childof = t.taskid) countchildren tasks t t.childof = 0

mysql sql subquery hierarchical-data

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