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wendigo
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Remote query cannot be constructed with empty columns list
wendigo
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| ResultSetMetaData metadata = preparedStatement.getMetaData(); | ||
| if (metadata == null) { | ||
| // SingleStore returns empty metadata instead of a null value | ||
| if (metadata == null || metadata.getColumnCount() == 0) { |
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As I've stated in a commit message: constructing Query PTF without columns doesn't make sense any way so this condition seems fine to me.
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This method is supposed to create a table handle for a PreparedQuery. Apparently, it is able to create a valid TableHandle with no columns. Let the caller take responsibility of handling the "no columns" condition. A TableHandle without columns might make no sense for a Table Function, but it might be OK in some other context (in the future). If a TableHandle with no columns is never OK, then maybe we miss a check in the JdbcTableHandle constructor?
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Can relation have no columns?
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A relation should have at least one column (though there exist sub-plans with no columns as a result of optimization).
My point is that a TH with no columns could still be potentially useful if it represents e.g. an insert. Adding the column on Trino side would not be a big issue.
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Replaces #12696
All tests are passing locally