series limit put to 0 results in no subquery but gives stupid parsing error (on postgre ?)

[maartenvanwauwe]

version:0.19.1
if I set the series limit to 100 -> query works
SELECT tenant AS tenant,
ymd_ts AS timestamp,
SUM(myschema.marathonreservation.weightedtotal) AS sum__weightedtotal
FROM myschema.marathonreservation
JOIN
(SELECT tenant AS tenant,
SUM(myschema.marathonreservation.weightedtotal) AS mme_inner__
FROM myschema.marathonreservation
WHERE ymd_ts >= '1917-09-14 00:00:00'
AND ymd_ts <= '2017-09-14 14:21:08'
GROUP BY tenant
ORDER BY mme_inner__ DESC
LIMIT 100) AS anon_1 ON tenant = tenant__
WHERE ymd_ts >= '1917-09-14 00:00:00'
AND ymd_ts <= '2017-09-14 14:21:08'
GROUP BY tenant,
ymd_ts
ORDER BY sum__weightedtotal DESC
LIMIT 5000

if I remove the series limit (by putting on 0) -> '>' not supported between instances of 'str' and 'int'
SELECT tenant AS tenant,
ymd_ts AS __timestamp,
SUM(myschema.marathonreservation.weightedtotal) AS sum__weightedtotal
FROM myschema.marathonreservation
WHERE ymd_ts >= '1917-09-14 00:00:00'
AND ymd_ts <= '2017-09-14 14:21:35'
GROUP BY tenant,
ymd_ts
ORDER BY sum__weightedtotal DESC
LIMIT 5000

Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/superset/viz.py", line 251, in get_payload
data = self.get_data(df)
File "/usr/local/lib/python3.6/site-packages/superset/viz.py", line 916, in get_data
df = self.process_data(df)
File "/usr/local/lib/python3.6/site-packages/superset/viz.py", line 865, in process_data
values=fd.get('metrics'))
File "/usr/local/lib/python3.6/site-packages/pandas/core/reshape/pivot.py", line 160, in pivot_table
table = table.sort_index(axis=1)
File "/usr/local/lib/python3.6/site-packages/pandas/core/frame.py", line 3243, in sort_index
labels = labels._sort_levels_monotonic()
File "/usr/local/lib/python3.6/site-packages/pandas/core/indexes/multi.py", line 1240, in _sort_levels_monotonic
indexer = lev.argsort()
File "/usr/local/lib/python3.6/site-packages/pandas/core/indexes/base.py", line 2091, in argsort
return result.argsort(*args, **kwargs)
TypeError: '>' not supported between instances of 'str' and 'int'

[xrmx]

First please follow the issue template, second this is a duplicate of #3029 so close.