Rstudio-server 中 sql 查询的空结果

Question

I'm trying to get data from MySQL DB into Rstudio-server. My actions are like

mydb = dbConnect(MySQL(), user='user', password='password', dbname='dbname', host='localhost')
query <- stri_paste('select sellings.updated_at AS Up_Date, concat(item_parameters.title, " ", ad_attributes.int_value) AS Class, CONCAT(geos.name, " ", geos.kind) AS place, geos.lon, geos.lat, sellings.price AS price, ((geo_routes.distance*2/1000 + 100)) AS delivery_cost FROM sellings, users, item_parameters, ad_attributes, geos, geo_routes WHERE users.encrypted_password!="" && item_parameters.title="Класс" && sellings.price IS NOT NULL && ad_attributes.int_value IS NOT NULL AND users.id=sellings.user_id AND item_parameters.id=ad_attributes.item_parameter_id AND sellings.id = ad_attributes.ad_id AND sellings.geo_guid = geos.guid AND geos.routable_guid = geo_routes.src_guid AND geo_routes.distance = (SELECT geo_routes.distance FROM geo_routes, geos WHERE geos.guid = sellings.geo_guid AND geo_routes.src_guid = geos.routable_guid AND geo_routes.dst_guid = (SELECT geos.routable_guid FROM geos WHERE geos.name = "Воронеж" && geos.kind = "г")) ORDER BY Up_Date;')
rs = dbGetQuery(mydb, query)

And I get an empty dataframe. But when I do the same with my local DB everything is OK. The query takes a pretty long time, about 3 minutes, but it works properly. Moreover the same query works right from the command line in MySQL. On the server, it takes about 4 seconds. OS of server is Debian 7, OS of local machine is Win 8. Any idea?

Answer 1

Sometimes when querying from the command line the default schema has been set in a previous command. This command doesn't carry over to R so the exact same query from a command line to a R session might not work. Maybe check the dbname.

Answer 2

Insert the below statements in your SQL query

SET NOCOUNT ON
SET ANSI_WARNINGS OFF

It worked for me