Bug: NonReserved keyword "interval" can't be column name
Status: Resolved | Priority: Major | Resolution: Fixed
Created: 24/Feb/23 09:42
Affects Version/s: 3.2.3

INTERVAL is a Non-Reserved keyword in spark. "Non-Reserved keywords" have a special meaning in particular contexts and can be used as identifiers in other contexts. So by design, interval can be used as a column name.
{code:java}
scala> spark.sql("select interval from mytable")
org.apache.spark.sql.catalyst.parser.ParseException:
at least one time unit should be given for interval literal(line 1, pos 7)== SQL ==
select interval from mytable
-------^^^  at org.apache.spark.sql.errors.QueryParsingErrors$.invalidIntervalLiteralError(QueryParsingErrors.scala:196)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$parseIntervalLiteral$1(AstBuilder.scala:2481)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.parseIntervalLiteral(AstBuilder.scala:2466)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitInterval$1(AstBuilder.scala:2432)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitInterval(AstBuilder.scala:2431)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitInterval(AstBuilder.scala:57)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$IntervalContext.accept(SqlBaseParser.java:17308)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitIntervalLiteral(SqlBaseBaseVisitor.java:1581)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$IntervalLiteralContext.accept(SqlBaseParser.java:16929)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitConstantDefault(SqlBaseBaseVisitor.java:1511)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$ConstantDefaultContext.accept(SqlBaseParser.java:15905)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitValueExpressionDefault(SqlBaseBaseVisitor.java:1392)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$ValueExpressionDefaultContext.accept(SqlBaseParser.java:15298)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.typedVisit(AstBuilder.scala:61)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.expression(AstBuilder.scala:1412)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitPredicated$1(AstBuilder.scala:1548)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitPredicated(AstBuilder.scala:1547)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitPredicated(AstBuilder.scala:57)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$PredicatedContext.accept(SqlBaseParser.java:14745)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitExpression(SqlBaseBaseVisitor.java:1343)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$ExpressionContext.accept(SqlBaseParser.java:14606)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.typedVisit(AstBuilder.scala:61)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.expression(AstBuilder.scala:1412)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitNamedExpression$1(AstBuilder.scala:1434)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitNamedExpression(AstBuilder.scala:1433)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitNamedExpression(AstBuilder.scala:57)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$NamedExpressionContext.accept(SqlBaseParser.java:14124)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.typedVisit(AstBuilder.scala:61)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitNamedExpressionSeq$2(AstBuilder.scala:628)
  at scala.collection.immutable.List.map(List.scala:293)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitNamedExpressionSeq(AstBuilder.scala:628)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$withSelectQuerySpecification$1(AstBuilder.scala:734)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.withSelectQuerySpecification(AstBuilder.scala:728)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitRegularQuerySpecification$1(AstBuilder.scala:620)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitRegularQuerySpecification(AstBuilder.scala:608)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitRegularQuerySpecification(AstBuilder.scala:57)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$RegularQuerySpecificationContext.accept(SqlBaseParser.java:9679)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitQueryPrimaryDefault(SqlBaseBaseVisitor.java:846)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$QueryPrimaryDefaultContext.accept(SqlBaseParser.java:9184)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitQueryTermDefault(SqlBaseBaseVisitor.java:832)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$QueryTermDefaultContext.accept(SqlBaseParser.java:8953)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.typedVisit(AstBuilder.scala:61)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.plan(AstBuilder.scala:112)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitQuery$1(AstBuilder.scala:118)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitQuery(AstBuilder.scala:117)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitQuery(AstBuilder.scala:57)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$QueryContext.accept(SqlBaseParser.java:6398)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitChildren(AstBuilder.scala:71)
  at org.apache.spark.sql.catalyst.parser.SqlBaseBaseVisitor.visitStatementDefault(SqlBaseBaseVisitor.java:69)
  at org.apache.spark.sql.catalyst.parser.SqlBaseParser$StatementDefaultContext.accept(SqlBaseParser.java:1835)
  at org.antlr.v4.runtime.tree.AbstractParseTreeVisitor.visit(AbstractParseTreeVisitor.java:18)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.$anonfun$visitSingleStatement$1(AstBuilder.scala:78)
  at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:133)
  at org.apache.spark.sql.catalyst.parser.AstBuilder.visitSingleStatement(AstBuilder.scala:78)
  at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.$anonfun$parsePlan$1(ParseDriver.scala:78)
  at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parse(ParseDriver.scala:110)
  at org.apache.spark.sql.execution.SparkSqlParser.parse(SparkSqlParser.scala:51)
  at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parsePlan(ParseDriver.scala:77)
  at org.apache.spark.sql.SparkSession.$anonfun$sql$2(SparkSession.scala:616)
  at org.apache.spark.sql.catalyst.QueryPlanningTracker.measurePhase(QueryPlanningTracker.scala:111)
  at org.apache.spark.sql.SparkSession.$anonfun$sql$1(SparkSession.scala:616)
  at org.apache.spark.sql.SparkSession.withActive(SparkSession.scala:775)
  at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:613)
  ... 47 elided
{code}
Since there must be at least one time unit after the interval, why in SqlBaseParser.g4, the definition of interval is
{code:java}
interval
    : INTERVAL (errorCapturingMultiUnitsInterval | errorCapturingUnitToUnitInterval)?
    ;  {code}
instead of
{code:java}
interval
    : INTERVAL (errorCapturingMultiUnitsInterval | errorCapturingUnitToUnitInterval)
    ; {code}
If we remove the "?", we ensure that there must be at least one time unit after the interval from the parsing level