Incorrect column in CSV format when select field is function

[chloe-zh]

Example:

Index: kibana_sample_data_flights

Query:

POST _opendistro/_sql?format=csv
{
    "query": "select log(AvgTicketPrice) from kibana_sample_data_flights limit 5"
}

Result:

log(AvgTicketPrice),FlightNum,Origin,OriginLocation,DestLocation,FlightDelay,DistanceMiles,FlightTimeMin,OriginWeather,dayOfWeek,AvgTicketPrice,Carrier,FlightDelayMin,OriginRegion,FlightDelayType,DestAirportID,timestamp,Dest,FlightTimeHour,Cancelled,DistanceKilometers,OriginCityName,DestWeather,OriginCountry,DestCountry,DestRegion,OriginAirportID,DestCityName
6.472336294873528,JHB3J5V,Melbourne International Airport,"{lon=144.843002, lat=-37.673302}","{lon=-93.22180176, lat=44.88199997}",false,9441.687300483349,1012.9948537939384,Heavy Fog,4,646.9935382543698,Kibana Airlines,0,SE-BD,No Delay,MSP,2020-04-03T01:03:05,Minneapolis-St Paul International/Wold-Chamberlain Airport,16.883247563232306,false,15194.922806909077,Melbourne,Clear,AU,US,US-MN,MEL,Minneapolis
6.839912084672193,GQTQ1B3,London Gatwick Airport,"{lon=-0.190277994, lat=51.14810181}","{lon=141.6920013, lat=42.77519989}",false,5571.180557608165,471.89189491070294,Heavy Fog,4,934.4069613948874,ES-Air,0,GB-ENG,No Delay,CTS,2020-04-03T14:03:40,New Chitose Airport,7.864864915178383,false,8965.946003303356,London,Cloudy,GB,JP,SE-BD,LGW,Chitose / Tomakomai
5.8188328302884935,80V65VD,Shanghai Hongqiao International Airport,"{lon=121.3359985, lat=31.19790077}","{lon=12.3519, lat=45.505299}",false,5536.339466666921,424.27974774493384,Clear,4,336.5789802442783,ES-Air,0,SE-BD,No Delay,VE05,2020-04-03T06:55:15,Venice Marco Polo Airport,7.071329129082231,false,8909.87470264361,Shanghai,Hail,CN,IT,IT-34,SHA,Venice
5.452020493148166,XF0OU6C,Naples International Airport,"{lon=14.2908, lat=40.886002}","{lon=10.8885, lat=45.395699}",false,355.5783118615778,52.022529338596286,Cloudy,4,233.2289208440965,Logstash Airways,0,IT-72,No Delay,VR10,2020-04-03T19:09:19,Verona Villafranca Airport,0.8670421556432715,true,572.2478227245591,Naples,Thunder & Lightning,IT,IT,IT-34,NA01,Verona
6.290595154646786,TA2TQ3Y,Narita International Airport,"{lon=140.3860016, lat=35.76470184}","{lon=7.64963, lat=45.200802}",false,6127.111396898864,657.3753309287204,Rain,4,539.4743076328305,Logstash Airways,0,SE-BD,No Delay,TO11,2020-04-03T04:21:10,Turin Airport,10.956255515478672,false,9860.629963930805,Tokyo,Heavy Fog,JP,IT,IT-21,NRT,Torino

Expected output:

log(AvgTicketPrice)
6.472336294873528
6.839912084672193
5.8188328302884935
5.452020493148166
6.290595154646786