Sum should return 0 if no edge exists, also max( <variable>, 0) should work #4158
Description
What version of Dgraph are you using?
v1.0.17
Have you tried reproducing the issue with the latest release?
On your site. I ran this (and reproduced) on website with the blade runner example
What is the hardware spec (RAM, OS)?
MBP 2017 16GB Ram, running inside docker
Steps to reproduce the issue (command/config used to run Dgraph).
{
bladerunner(func: eq(name@en, "Blade Runner")) {
uid
name@en
initial_release_date
netflix_id
youDontHaveThisEdge {
B as count(~provideTag)
}
mediaCount: sum(val(B))
}
}
Expected behaviour and actual result.
Expected behaviour:
mediaCount should be 0
actual results:
Notice that mediaCount is absent from the response
{
"data": {
"bladerunner": [
{
"uid": "0x394c",
"name@en": "Blade Runner",
"initial_release_date": "1982-06-25T00:00:00Z",
"netflix_id": "70083726",
}
]
}
}
My current workaround:
{
bladerunner(func: eq(name@en, "Blade Runner")) {
uid
name@en
initial_release_date
netflix_id
youDontHaveThisEdge {
B as count(~provideTag)
}
mediaCount as mediaCount: sum(val(B))
mathZero as math(0)
mediaCount2: math( max(mediaCount, mathZero) )
}
}
which returns:
{
"data": {
"bladerunner": [
{
"uid": "0x394c",
"name@en": "Blade Runner",
"initial_release_date": "1982-06-25T00:00:00Z",
"netflix_id": "70083726",
"val(mathZero)": 0,
"mediaCount2": 0
}
]
}
}
Keep in mind, I also got forced to make a variable 'math(0)' which seems like another bug, I can't put max( , 0), it returns nothing. If this is a different bug you can reproduce it with the above command as well.