amaliujia commented on a change in pull request #1588: [CALCITE-3381] Unparse
to correct BigQuery interval syntax: "INTERVAL…
URL: https://github.com/apache/calcite/pull/1588#discussion_r350482904
##########
File path:
core/src/main/java/org/apache/calcite/sql/dialect/BigQuerySqlDialect.java
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@@ -154,6 +158,55 @@ public BigQuerySqlDialect(SqlDialect.Context context) {
}
}
+ /** BigQuery interval syntax: INTERVAL int64 time_unit. */
+ @Override public void unparseSqlIntervalLiteral(
+ SqlWriter writer, SqlIntervalLiteral literal, int leftPrec, int
rightPrec) {
+ SqlIntervalLiteral.IntervalValue interval =
+ (SqlIntervalLiteral.IntervalValue) literal.getValue();
+ writer.keyword("INTERVAL");
+ if (interval.getSign() == -1) {
+ writer.print("-");
+ }
+ Long intervalValueInLong;
+ try {
+ intervalValueInLong = Long.parseLong(literal.getValue().toString());
+ } catch (NumberFormatException e) {
+ throw new RuntimeException("Only INT64 is supported as the interval
value for BigQuery.");
+ }
+ writer.literal(intervalValueInLong.toString());
+ unparseSqlIntervalQualifier(writer, interval.getIntervalQualifier(),
+ RelDataTypeSystem.DEFAULT);
+ }
+
+ @Override public void unparseSqlIntervalQualifier(
+ SqlWriter writer, SqlIntervalQualifier qualifier, RelDataTypeSystem
typeSystem) {
+ final String start = validate(qualifier.timeUnitRange.startUnit).name();
+ if (qualifier.timeUnitRange.endUnit == null) {
+ writer.keyword(start);
+ } else {
+ throw new RuntimeException("Range time unit is not supported for
BigQuery.");
+ }
+ }
+
+ private TimeUnit validate(TimeUnit timeUnit) {
+ switch (timeUnit) {
+ case MICROSECOND:
+ case MILLISECOND:
+ case SECOND:
+ case MINUTE:
+ case HOUR:
+ case DAY:
+ case WEEK:
+ case MONTH:
+ case QUARTER:
+ case YEAR:
+ case ISOYEAR:
+ return timeUnit;
+ default:
+ throw new RuntimeException("Time unit " + timeUnit + " is not supported
for BigQuery.");
Review comment:
Tried to have a test to this exception, but it seems like those
not-supported time unit cannot fit into `INTERVAL val timeunit` syntax. For
example, Parser will reject `INTERVAL '10' NANOSECOND`.
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