should be it

external/duckdb/tools/juliapkg/test/test_decimals.jl

@@ -0,0 +1,89 @@
+# test_decimals.jl
+
+
+@testset "Test decimal support" begin
+    con = DBInterface.connect(DuckDB.DB)
+
+    results = DBInterface.execute(
+        con,
+        "SELECT 42.3::DECIMAL(4,1) a, 4923.3::DECIMAL(9,1) b, 421.423::DECIMAL(18,3) c, 129481294.3392::DECIMAL(38,4) d"
+    )
+
+    # convert to DataFrame
+    df = DataFrame(results)
+    @test names(df) == ["a", "b", "c", "d"]
+    @test size(df, 1) == 1
+    @test df.a == [42.3]
+    @test df.b == [4923.3]
+    @test df.c == [421.423]
+    @test df.d == [129481294.3392]
+
+    DBInterface.close!(con)
+end
+
+# test returning decimals in a table function
+function my_bind_function(info::DuckDB.BindInfo)
+    DuckDB.add_result_column(info, "a", FixedDecimal{Int16, 0})
+    DuckDB.add_result_column(info, "b", FixedDecimal{Int32, 1})
+    DuckDB.add_result_column(info, "c", FixedDecimal{Int64, 2})
+    DuckDB.add_result_column(info, "d", FixedDecimal{Int128, 3})
+    return missing
+end
+
+mutable struct MyInitStruct
+    pos::Int64
+
+    function MyInitStruct()
+        return new(0)
+    end
+end
+
+function my_init_function(info::DuckDB.InitInfo)
+    return MyInitStruct()
+end
+
+function my_main_function(info::DuckDB.FunctionInfo, output::DuckDB.DataChunk)
+    init_info = DuckDB.get_init_info(info, MyInitStruct)
+
+    a_array = DuckDB.get_array(output, 1, Int16)
+    b_array = DuckDB.get_array(output, 2, Int32)
+    c_array = DuckDB.get_array(output, 3, Int64)
+    d_array = DuckDB.get_array(output, 4, Int128)
+    count = 0
+    multiplier = 1
+    for i in 1:(DuckDB.VECTOR_SIZE)
+        if init_info.pos >= 3
+            break
+        end
+        a_array[count + 1] = 42 * multiplier
+        b_array[count + 1] = 42 * multiplier
+        c_array[count + 1] = 42 * multiplier
+        d_array[count + 1] = 42 * multiplier
+        count += 1
+        init_info.pos += 1
+        multiplier *= 10
+    end
+
+    DuckDB.set_size(output, count)
+    return
+end
+
+@testset "Test returning decimals from a table functions" begin
+    con = DBInterface.connect(DuckDB.DB)
+
+    arguments::Vector{DataType} = Vector()
+    DuckDB.create_table_function(con, "my_function", arguments, my_bind_function, my_init_function, my_main_function)
+    GC.gc()
+
+    # 3 elements
+    results = DBInterface.execute(con, "SELECT * FROM my_function()")
+    GC.gc()
+
+    df = DataFrame(results)
+    @test names(df) == ["a", "b", "c", "d"]
+    @test size(df, 1) == 3
+    @test df.a == [42, 420, 4200]
+    @test df.b == [4.2, 42, 420]
+    @test df.c == [0.42, 4.2, 42]
+    @test df.d == [0.042, 0.42, 4.2]
+end