LTRIM in PySpark notebook returns empty string

Hi smoqt ,

Thank you for reaching out with your query about the LTRIM behavior in Microsoft Fabric.

As per my understanding, lakehouse SQL endpoint uses T-SQL’s LTRIM(string, characters), correctly trimming leading '0' to return '11160027'. Whereas Standard PySpark’s ltrim(str) only removes whitespace, not specific characters, which caused the empty string. However, Fabric extends ltrim to support ltrim(trimstr, str).

In Fabric, ltrim('0', '0011160027') works due to a Fabric-specific extension, trimming leading '0' to return '11160027'.

SQL Endpoint LTRIM('0', '0011160027') ,returns '0' because T-SQL’s LTRIM treats '0' as the string to trim, with no leading '0011160027' to remove.

Differences between T-SQL and PySpark can be tricky. Use regexp_replace in PySpark for portability:

     from pyspark.sql.functions import regexp_replace

     df = df.withColumn('trimmed', regexp_replace('NumberStr', '^0+', ''))

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Thank you