JSON/Text Parsing in DAX

[DreamToGet]

Hi,

I have a column 'Results' with information stored as string (in JSON format) and would like to parse this string and get only necessary information from this column. After reading through support forums, I understood the easier way is to use 'Parse JSON' via transform data and retrieve only the needed info but I can't use it as it breaks Query folding for 'Incremental Refresh'.

[Note: The entire string in 'Results' column in too large and I have only pasted the relevant part]

In order to achieve this, I am trying to create a new column with DAX query as pasted below. I would like to perform the below operations.

1. Retrieve the info in value field after first 'Output' string appearance (as highlighted below)
2. If 'Output' string is not available (or) value is empty (or) value is nor numeric, return '0' or null.
3. Convert the output to decimal format.

Can you have a look at the DAX query and please let me know what am I doing wrong? Also, is there any other better/efficient way to achieve this? Would appreciate your help on this.

Index	Serial Number	Results
1	TST2334	{"MeasuredValue":[{"Name":"TestType","Value":"SingleValueMeasurement","MetricUnit":null,"MeasurementUnit":null},{"Name":"Output","Value":"","MetricUnit":null,"MeasurementUnit":null}], .......................................
2	DY75677	{"MeasuredValue":[{"Name":"TestType","Value":"NonMeasurement","MetricUnit":null,"MeasurementUnit":null}], ..........................
3	DCQ7869	{"MeasuredValue":[{"Name":"TestType","Value":"SingleValueMeasurement","MetricUnit":null,"MeasurementUnit":null},{"Name":"Output","Value":"264","MetricUnit":null,"MeasurementUnit":""}, .............................
4	UAE9354	{"MeasuredValue":[{"Name":"TestType","Value":"SingleValueMeasurement","MetricUnit":null,"MeasurementUnit":null},{"Name":"Output","Value":"88.23","MetricUnit":null,"MeasurementUnit":"dB"}, ....................
5	F1R3496	{"MeasuredValue":[{"Name":"TestType","Value":"SingleValueMeasurement","MetricUnit":null,"MeasurementUnit":null}],"InputParameter":[{"Name":"TestFunctionVisibility","Value":"True","MetricUnit":null,"MeasurementUnit":null}
6	UAE9377	{"MeasuredValue":[{"Name":"TestType","Value":"CurveMeasurement","MetricUnit":null,"MeasurementUnit":null},{"Name":"Output","Value":"83.64","MetricUnit":null,"MeasurementUnit":............

Output =
VAR FindOutput =
    IFERROR ( SEARCH ( "Output", [Results],, 1 ), 1 )
VAR FindValue =
    IFERROR ( SEARCH ( "Value", [Results], FindOutput, 1 ), 1 )
VAR FindColon =
    IFERROR ( SEARCH ( ":", [Results], FindValue, 1 ), 1 )
VAR FindComma =
    IFERROR ( SEARCH ( ",", [Results], FindColon, 1 ), 1 )
VAR temp =
    VALUE ( FindComma - FindColon - 3 )
RETURN
    IFERROR ( MID ( [Results], VALUE ( FindColon + 2 ), temp ), "null" )

Thanks in advance!

[v-luwang-msft · Accepted solution]

Hi @DreamToGet ,

Try to adjust your measure to below:

Output = 
VAR FindOutput =
    IFERROR ( SEARCH ( "Output", [Results],, 1 ), 1 )
VAR FindValue =
    IFERROR ( SEARCH ( "Value", [Results], FindOutput, 1 ), 1 )
VAR FindColon =
    IFERROR ( SEARCH ( ":", [Results], FindValue, 1 ), 1 )
VAR FindComma =
    IFERROR ( SEARCH ( ",", [Results], FindColon, 1 ), 1 )
VAR temp =
    VALUE ( FindComma - FindColon - 3 )
RETURN
    IF (
        IFERROR ( INT ( MID ( [Results], VALUE ( FindColon + 2 ), temp ) ), BLANK () )
            <> BLANK (),
        FORMAT ( MID ( [Results], VALUE ( FindColon + 2 ), temp ), "Fixed" ),
        BLANK ()
    )

Final get :

Wish it is helpful for you!

Best Regards

Lucien

[lbendlin]

uh, you make it unnecessary hard on yourself.  Power Query has a built-in JSON parser. Maybe you can do the transforms there?