database - Post-hoc inventory/queue size query -

say have list of events/tasks time stamps created, completed.

examples:

• customer entering queue, being served
• business process starting , completing
• order received, order dispatched

also related fill, take events:

• pay goes bank account, pay bills, buy food, go movies
• fuel tanker replenishes gas station, customers purchase fuel
• store receives stock, customers purchase stock

now have huge list of data. don't know starting inventory levels because i've come in after beginning , can't view current inventory either.

how can query data can tell current inventory levels, queue size, etc @ given time? or start plot size of inventory on time line?

edit: i'll explain specific requirements in more detail

our warehouse management sytem contains historical data each task occurs. doesn't capture state of pick bin event happens, how picked or how replenished. have cycle count tasks show how stock in pick bin. trying find way of tying these 3 processes together, replenishment, picking, cycle counts, can plot on time line:

• how many tasks waiting
• current stock levels

at moment data, have figured out how plot how many tasks created or completed in period of time, or how picked, based off time stamps task.

now reason data track performance, under/over allocation of staff , indentifying config issues causing performance issues.

now have huge list of data. don't know starting inventory levels because i've come in after beginning , can't view current inventory either.

how can query data can tell current inventory levels, queue size, etc @ given time?

the short answer is: "you can't."

if have deposits/withdrawals without opening balance or closing balance there no way track actual current balance because have no reference point start. could track relative balance (or inventory level, or whatever) assuming starting balance of 0, or 100, or 1000, or value like.

as plotting data, excel logical place start task that.