[ANN] SQLdf - SQL for Julia types implementing Tables.jl

Latest version 0.2.0 of SQLdf uses as default RDB engine SQLite.jl instead accessing R/sqldf via RCall. This latest version and its default has the following new features:

  • More responsive access to SQLite
  • Ability to query any Julia type implementing Tables.jl interface
  • Ability to mix in the same query Julia types implementing Tables.jl interface
  • @sqldf macro

Regardless the types used in the query the result will always be a DataFrame. Below there is an example joining a DataFrame and a TimeArray with duplicated column names.

Note: In this version it is still possible to access R/sqldf by using the command setRDB("R"), to set sqldf's default back to SQLite.jl we need to use setRDB("SQLite").

using SQLdf, TimeSeries
DF = DataFrame(a=1:14,  b=14:-1:1, c = split("Julia is great",""))
TA = TimeArray(Date(2021, 1, 1):Day(1):Date(2021, 1, 14), 1:14)

julia> @sqldf "select * from TA join DF where TA.A = DF.a"
14×5 DataFrame
 Row │ timestamp   A      a:1    b      c      
     │ Date        Int64  Int64  Int64  String 
─────┼─────────────────────────────────────────
   1 │ 2021-01-01      1      1     14  J
   2 │ 2021-01-02      2      2     13  u
   3 │ 2021-01-03      3      3     12  l
   4 │ 2021-01-04      4      4     11  i
   5 │ 2021-01-05      5      5     10  a
   6 │ 2021-01-06      6      6      9
   7 │ 2021-01-07      7      7      8  i
   8 │ 2021-01-08      8      8      7  s
   9 │ 2021-01-09      9      9      6
  10 │ 2021-01-10     10     10      5  g
  11 │ 2021-01-11     11     11      4  r
  12 │ 2021-01-12     12     12      3  e
  13 │ 2021-01-13     13     13      2  a
  14 │ 2021-01-14     14     14      1  t
12 Likes