What causes SYNAPSE_SQL_0006?

The external file format (Parquet, CSV, ORC) does not match the data being written. Column count or data types in the SELECT do not match the external table schema. The delimiter or encoding specified in the format does not match the source

How do I fix SYNAPSE_SQL_0006?

Step 1: Review the EXTERNAL FILE FORMAT definition: `SELECT * FROM sys.external_file_formats;`. Step 2: Verify the column types in the SELECT match the external table definition.. Step 3: For Parquet, ensure all columns have supported types (Synapse does not support all Parquet types).. Step 4: Re-create the external file format with the correct settings and re-run CETAS.

High severityschema

Power BI Refresh Error:
SYNAPSE_SQL_0006

What does this error mean?

A CREATE EXTERNAL TABLE AS SELECT (CETAS) operation failed due to a mismatch between the file format definition and the actual data.

Common causes

1The external file format (Parquet, CSV, ORC) does not match the data being written
2Column count or data types in the SELECT do not match the external table schema
3The delimiter or encoding specified in the format does not match the source

How to fix it

1Step 1: Review the EXTERNAL FILE FORMAT definition: `SELECT * FROM sys.external_file_formats;`
2Step 2: Verify the column types in the SELECT match the external table definition.
3Step 3: For Parquet, ensure all columns have supported types (Synapse does not support all Parquet types).
4Step 4: Re-create the external file format with the correct settings and re-run CETAS.

Frequently asked questions

How do I monitor for CETAS File Format Mismatch in my pipelines?

Connect Azure Data Factory to MetricSign — failed pipeline runs trigger incident alerts with the root cause, so your team is notified before users notice report failures.

Official documentation: https://learn.microsoft.com/en-us/azure/synapse-analytics/sql/troubleshoot-synapse-studio