MySQL Date conversion failure

New to Julia
1

I have managed to get MySQL.jl working, and it seems a very handy utility.

[I would be grateful for any up-to-date documentation on it - I had to figure it out from trial and error]

I managed to get MySQL.connect working and to get MySQL.query working for most of my needs.

However, there is one issue I can’t seem to overcome, which is that queries involving dates or times seem to fail over a conversion issue:

ERROR: MethodError: Cannot convert an object of type Type{DateTime} to an object of type Unsigned

I saw some reference to this online from some time ago, and a reference to setting something to zero in the connection string, but I could not seem to fit anything like that into MySQL.connect, or indeed to solve the problem using the Dates package.

It is probably something simple, but I just can’t seem to find it documented anywhere, and I would appreciate any help,

Thanks in advance

[Update: I had some success using ‘CAST’ conversion in my query, but any other suggestion avoiding conversion to ‘CHAR’ (string) would be better]

2

Do you have the full error message? Do you know what line of code is the issue?

3

Just a minute…

Closest candidates are:
convert(::Type{T<:Number}, ::T<:Number) where T<:Number at number.jl:6
convert(::Type{T<:Number}, ::Number) where T<:Number at number.jl:7
convert(::Type{T<:Integer}, ::Ptr) where T<:Integer at pointer.jl:23

Stacktrace:
[1] unsigned(::Type) at ./int.jl:161
[2] julia_type(::UInt32, ::Bool, ::Bool) at /home/davide/.julia/packages/MySQL/R2gKS/src/types.jl:62
[3] #3 at ./none:0 [inlined]
[4] iterate(::Base.Generator{Array{MySQL.API.MYSQL_FIELD,1},getfield(MySQL, Symbol(“##3#5”))}, ::Int64) at ./generator.jl:47
[5] append_any(::Any, ::Vararg{Any,N} where N) at ./essentials.jl:728
[6] #Query#1(::Bool, ::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::Type{MySQL.Query}, ::MySQL.Connection, ::String) at /home/davide/.julia/packages/MySQL/R2gKS/src/types.jl:94
[7] MySQL.Query(::MySQL.Connection, ::String) at /home/davide/.julia/packages/MySQL/R2gKS/src/types.jl:79
[8] top-level scope at REPL[49]:1

Thanks for any help [stepping away for an hour]

Back now and will keep an eye. You should be able to recreate
the error by just trying a select query on a Date field in a db table.

4

I’m not sure what could be the issue. I do not use MySQL.jl myself, although I was about to start using it. If no one else responds, then you could try submitting an issue here: https://github.com/JuliaDatabases/MySQL.jl/issues

This seems like it might be a bug.

5

Thanks, I do think so as the example I tried is very basic. However, if you use CAST to convert the dates in the SQL syntax within MySQL, then that seems a sensible workaround and no too much trouble.

Apart from this, I was surprised to see how easy MySQL.jl is to use and how handy it is! Well-done coders!