[CALCITE-1772] Add a hook to allow RelNode expressions to be executed by JDBC driver

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.13.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 02/May/17 03:21
• Updated: 27/Feb/24 22:23
• Resolved: 02/May/17 06:47

Description

Add a hook to allow RelNode expressions to be executed by JDBC driver in the same way that SQL would.

If you set Hook.STRING_TO_QUERY you can provide a function that creates a CalcitePrepare.Query object; this can wrap a String (SQL query), RelNode tree or Queryable.

In tests, you can call convenience method AssertQuery.withRel, whose implementation sets the hook. For example,

    sql("?")
        .withRel(new Function<RelBuilder, RelNode>() {
          public RelNode apply(RelBuilder b) {
            // select count(*) as c
            // from foodmart.foodmart
            // where product_id < cast(10 as varchar)
            return b.scan("foodmart", "foodmart")
                .filter(
                    b.call(SqlStdOperatorTable.LESS_THAN,
                        b.field("product_id"),
                        b.getRexBuilder().makeCall(
                            b.getTypeFactory().createSqlType(SqlTypeName.INTEGER),
                            SqlStdOperatorTable.CAST,
                            ImmutableList.<RexNode>of(b.literal("10")))))
                .aggregate(b.groupKey(), b.countStar("c"))
                .build();
          }
        })
    .returns("c=45");

Issue Links

• is depended upon by: CALCITE-1769 Push Filters down to druid when there a cast to numeric