Support zero_date (#200)

Author: quinnj

src/execute.jl

@@ -62,13 +62,16 @@ function cast(::Type{T}, ptr, len) where {T}
 end
 
 const DATETIME_OPTIONS = Parsers.Options(dateformat=dateformat"yyyy-mm-dd HH:MM:SS.s")
+const ZERO_DATE = Vector{UInt8}("0000-00-00 00:00:00")
 
 function cast(::Type{DateTime}, ptr, len)
     buf = unsafe_wrap(Array, ptr, len)
     try
         x, code, pos = Parsers.typeparser(DateTime, buf, 1, len, buf[1], Int16(0), DATETIME_OPTIONS)
         if code > 0
             return x
+        elseif buf == ZERO_DATE
+            return DateTime(0)
         end
     catch e
         e isa InexactError && API.dateandtime_warning()
@@ -89,6 +92,8 @@ function cast(::Type{DateAndTime}, ptr, len)
             tm += Dates.Microsecond(y)
         end
         return DateAndTime(dt, tm)
+    elseif buf == ZERO_DATE
+        return DateAndTime(Date(0), Time(0))
     end
     casterror(DateAndTime, ptr, len)
 end

test/runtests.jl

@@ -336,6 +336,13 @@ ct = (x = UInt8[1, 2, 3],)
 MySQL.load(ct, conn, "test194")
 ct2 = columntable(DBInterface.execute(conn, "select * from test194"))
 
+# https://github.com/JuliaDatabases/MySQL.jl/issues/186
+DBInterface.execute(conn, "SET SESSION SQL_MODE=''")
+dt = DBInterface.execute(conn, "SELECT CAST('0000-00-00' as DATETIME) as dt ") |> Tables.columntable
+@test dt.dt[1] == DateTime(0)
+dt = DBInterface.execute(conn, "SELECT CAST('0000-00-00' as DATETIME) as dt "; mysql_date_and_time=true) |> Tables.columntable
+@test dt.dt[1].date == DateTime(0)
+
 # 156
 res = DBInterface.execute(conn, "select * from Employee")
 DBInterface.close!(conn)