Truncation vs. Rounding

TDV truncates values to the right of the decimal point when converting a NUMERIC, DECIMAL, FLOAT, or DOUBLE to an INTEGER type. Some data sources do rounding; others match TDV behavior. The SQL standard leaves implementation up to the vendor.

Because of this difference, results can differ when:

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Functions are applied that perform such conversions

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Numeric data is CAST to an INTEGER type

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Type promotion is performed during caching

In most cases, the TDV query engine warns the user when it detects a mismatch of this kind. However, the query engine cannot detect all such mismatches, and the query engine cannot normalize data source behavior for federated queries.