Mihai Budiu created CALCITE-7840:
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Summary: REAL literals should be represented with reduced precision
Key: CALCITE-7840
URL: https://issues.apache.org/jira/browse/CALCITE-7840
Project: Calcite
Issue Type: Bug
Components: core
Affects Versions: 1.42.0
Reporter: Mihai Budiu
Assignee: Mihai Budiu
When casting a numeric literal to a REAL value Calcite still stores the value
using a Java Double. That's fine, but the stored value should be first computed
using the REAL precision, and then saved as a DOUBLE.
This is pretty subtle. This is the result of a quidem test today:
{code:java}
values (cast(0.1e0 as real) = cast(0.1 as real),
cast(cast(0.1e0 as real) as double) = cast(cast(0.1 as real) as double),
cast(0.1e0 as real) = 0.1e0);
+--------+--------+--------+
| EXPR$0 | EXPR$1 | EXPR$2 |
+--------+--------+--------+
| false | false | true |
+--------+--------+--------+
(1 row) {code}
This is the expected result:
{code:java}
+--------+--------+--------+
| EXPR$0 | EXPR$1 | EXPR$2 |
+--------+--------+--------+
| true | true | false |
+--------+--------+--------+ {code}
(Postgres at least agrees with the last result, with some qualifications
regarding how Postgres types literals)
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