Unsupported SQL type '{columnType}' for column 'VARBINARY'
I want to assign NULL values to certain columns in a SQL transform:
SELECT NULL as 'column_x', NULL as 'column_y', column_z FROM Table_1
The dataflow gives the following error: Unsupported SQL type '{columnType}' for column 'VARBINARY'
This is because from what I understood from another post in Dojo: you cannot assign NULL values in MySQL to a text column. However, we're currently doing that in another SQL transform in another dataflow!! Why does it run in that dataflow but not in this dataflow I fail to udnerstand! We assign NULL values to a text column in that dataflow
I did a workaround where I started to assign blank values instead of NULL.
SELECT '' as 'column_x', '' as 'column_y', column_z FROM Table_1
It worked! However I do a COALESCE function in the next transform, such as the following:
COALESCE(column_x, column_y, column_z)
Now because column_x is non-null, it starts to assign column_x values to above. However, It actually should've been null (I only assigned blank to column_x and column_y as a workaround). The true result of above should be column_z
Could someone help me here please?
Best Answer
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Hi @hamza_123
I believe Domo has the ability you to utilize the NULLIF() function where it will return if a field meets a specific column.
COALESCE(NULLIF(column_x, ''), NULLIF(column_y, ''), NULLIF(column_z, ''))
If not you could wrap it in CASE statements.
CASE WHEN `column_x` <> '' THEN `column_x` WHEN `column_y` <> '' THEN `column_y` ELSE `column_z` END
As for your original question, NULLs should be allowed under a string column. Are you only returning NULL or is it mixed with other string values?
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Answers
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The NULLIFF is a very smart way to look at things. Let me try that and get back to you here!
Thankyou.
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SpoilerThe following did not give me an error when trying it in Domo's MySQL :
SELECT CAST(NULL as char) as mycol
You could try that and see if that works for you.
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**Please mark as accepted the ones who solved your issue.0 -
It worked! ThankYou
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