Hello @At_AC,
Thanks for your question! Looks like you want to perform some joins with flux. What version of influxdb are you using? You’ll have to use at least 1.7.6 to enable flux. I recommend taking a look at this example in the spec and this blog for examples on how to perform a join in influx 
It’ll end up looking something like
join1 = join(tables: {t1: table1, t2: table2}, on: ["_time", "_field"])
join2 = join(tables: {t3: table1, t4: table2}, on: ["_time", "_field"])
join_final = join(tables: {j1: join1, j2: join2}, on: ["_time", "_field"])
*multi-stream joins are coming soon IMPL#83
