If you want exact precision to a number of decimal digits, I'd recommend using the DECIMAL data type. Floating point can't exactly represent decimal numbers. If you're returning a floating point type from a query, then you don't have any real control over the display because it's basically a client-side formatting decision.E.g. your Java code that uses the JDBC drive could take the value and format it however it wants. You *might* be able to get the desired behaviour in impala-shell by using the round() function but that depends on some undocumented behaviour. I'd recommend looking at decimal.
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