Need help in Dataweave Transformation - mule

Question

I have the oracle database table CASH which contains below columns:
REGISTER DATE CASE BAG TYPE
1234 24-SEP-18 1123 112 A
1234 24-SEP-18 1124 113 S
1234 24-SEP-18 1123 116 S
1234 24-SEP-18 1124 117 A
7895 24-SEP-18 2568 119 A
7895 24-SEP-18 2568 118 S
Where the register number are the cash registers which can have multiple CASE linked to it and each CASE can have more than one BAG and Type attached to it. I want to transform it into below XML in Dataweave:
<ROOT>
<REGISTERS>
<REGISTER>1234</REGISTER>
<DATE>24-SEP-2018</DATE>
<DETAILS>
<BAG>1123</BAG>
<DETAIl>
<BAG>112</BAG>
<TYPE>A</TYPE>
</DETAIl>
<DETAIl>
<BAG>116</BAG>
<TYPE>S</TYPE>
</DETAIl>
</DETAILS>
<DETAILS>
<BAG>1124</BAG>
<DETAIl>
<BAG>113</BAG>
<TYPE>S</TYPE>
</DETAIl>
<DETAIl>
<BAG>117</BAG>
<TYPE>A</TYPE>
</DETAIl>
</DETAILS>
</REGISTERS>
<REGISTERS>
<REGISTER>7895</REGISTER>
<DATE>24-SEP-2018</DATE>
<DETAILS>
<BAG>2568</BAG>
<DETAIl>
<BAG>119</BAG>
<TYPE>A</TYPE>
</DETAIl>
<DETAIl>
<BAG>118</BAG>
<TYPE>S</TYPE>
</DETAIl>
</DETAILS>
</REGISTERS>
</ROOT>
Could you please give some pointers how can I achieve this in dataweave.
Thanks !!

Answer 1

Assuming you've already read the data from the database, you can use the following:
%dw 1.0
%output application/xml
---
ROOT: payload groupBy (($.REGISTER as :string) ++ ($.DATE as :string)) mapObject ((entries, number) -> {
REGISTERS: {
REGISTER: entries[0].REGISTER,
DATE: entries[0].DATE as :string {format: "yyyy-MM-dd"},
(entries groupBy $.CASE map DETAILS: {
CASE: $.CASE[0],
($ map DETAIL: {
BAG: $.BAG,
TYPE: $.TYPE
})
})
}
})