Convert a column from varchar to number in expression building window

Aami — Fri, 14 Mar 2025 20:49:07 GMT

Hi All,

I am trying to build a lookup from table A to Table B. I would like to convert one of the columns from varchar to number in expression builder where the condition is being defined for comparision purpose. Any kind of help is appreciated.

Thanks,

Re: Convert a column from varchar to number in expression building window

TimGarrod — Tue, 22 Sep 2020 22:05:48 GMT

Hi Aami - assuming this is a lookup in Compose for Data Warehouses - you will use whatever data conversion function(s) / syntax is used in your data warehouse environment. ComposeDW uses an E-LT paradigm to process data. Meaning it generates SQL for your target DW platform to process the data. Thus any expressions / transformation logic applied in ComposeDW uses your target platforms SQL functionality.

For example if SQL Server is your data warehouse platform - SQL Server provides CAST(X as [DATATYPE]) , CONVERT(DATATYPE,X) or TRY_CONVERT(DATATYPE,X) as data type casting operators.

If you are using Snowflake - CAST(X as DATATYPE) or the TRY_CAST(X as DATATYPE) functions support data type conversion.

Each DW environment provides its own functionality. It is a good practice to use "TRY_" functions in the event your VARCHAR data cannot be convert to numeric - it will prevent an error and you could even use Compose data validation functionality to route those records to an error mart if required.

Hope this helps.

Re: Convert a column from varchar to number in expression building window

Aami — Wed, 23 Sep 2020 06:38:13 GMT

Thank you Tim. I was able to use TRY_ in expression builder and it worked for me.

topic Convert a column from varchar to number in expression building window in Qlik Compose

Convert a column from varchar to number in expression building window

Re: Convert a column from varchar to number in expression building window

Re: Convert a column from varchar to number in expression building window