[CALCITE-4719] Add variants of RexSubQuery that collect sub-queries into MULTISET, ARRAY and MAP collections
In RexSubQuery, add methods `array`, `map`, `multiset`.
In RelBuilder, add methods `arrayQuery`, `mapQuery`,
`multisetQuery`.
Close apache/calcite#2582
diff --git a/core/src/main/java/org/apache/calcite/rex/RexSubQuery.java b/core/src/main/java/org/apache/calcite/rex/RexSubQuery.java
index 076c6ba..e1db6f8 100644
--- a/core/src/main/java/org/apache/calcite/rex/RexSubQuery.java
+++ b/core/src/main/java/org/apache/calcite/rex/RexSubQuery.java
@@ -108,7 +108,9 @@
/** Creates a scalar sub-query. */
public static RexSubQuery scalar(RelNode rel) {
final List<RelDataTypeField> fieldList = rel.getRowType().getFieldList();
- assert fieldList.size() == 1;
+ if (fieldList.size() != 1) {
+ throw new IllegalArgumentException();
+ }
final RelDataTypeFactory typeFactory = rel.getCluster().getTypeFactory();
final RelDataType type =
typeFactory.createTypeWithNullability(fieldList.get(0).getType(), true);
@@ -116,6 +118,33 @@
ImmutableList.of(), rel);
}
+ /** Creates an ARRAY sub-query. */
+ public static RexSubQuery array(RelNode rel) {
+ final RelDataTypeFactory typeFactory = rel.getCluster().getTypeFactory();
+ final RelDataType type =
+ typeFactory.createArrayType(rel.getRowType(), -1L);
+ return new RexSubQuery(type, SqlStdOperatorTable.ARRAY_QUERY,
+ ImmutableList.of(), rel);
+ }
+
+ /** Creates a MULTISET sub-query. */
+ public static RexSubQuery multiset(RelNode rel) {
+ final RelDataTypeFactory typeFactory = rel.getCluster().getTypeFactory();
+ final RelDataType type =
+ typeFactory.createMultisetType(rel.getRowType(), -1L);
+ return new RexSubQuery(type, SqlStdOperatorTable.MULTISET_QUERY,
+ ImmutableList.of(), rel);
+ }
+
+ /** Creates a MAP sub-query. */
+ public static RexSubQuery map(RelNode rel) {
+ final RelDataTypeFactory typeFactory = rel.getCluster().getTypeFactory();
+ final RelDataType type =
+ typeFactory.createMultisetType(rel.getRowType(), -1L);
+ return new RexSubQuery(type, SqlStdOperatorTable.MAP_QUERY,
+ ImmutableList.of(), rel);
+ }
+
@Override public <R> R accept(RexVisitor<R> visitor) {
return visitor.visitSubQuery(this);
}
diff --git a/core/src/main/java/org/apache/calcite/tools/RelBuilder.java b/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
index 5132636..df81877 100644
--- a/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
+++ b/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
@@ -928,6 +928,79 @@
return RexSubQuery.scalar(f.apply(this));
}
+ /** Creates an ARRAY sub-query.
+ *
+ * <p>For example,
+ *
+ * <pre>{@code
+ * b.scan("Depts")
+ * .project(
+ * b.field("deptno")
+ * b.arrayQuery(b2 ->
+ * b2.scan("Emps")
+ * .build()))
+ * }</pre>
+ *
+ * <p>is equivalent to the SQL
+ *
+ * <pre>{@code
+ * SELECT deptno, ARRAY (SELECT * FROM Emps)
+ * FROM Depts
+ * }</pre> */
+ @Experimental
+ public RexSubQuery arrayQuery(Function<RelBuilder, RelNode> f) {
+ return RexSubQuery.array(f.apply(this));
+ }
+
+ /** Creates a MULTISET sub-query.
+ *
+ * <p>For example,
+ *
+ * <pre>{@code
+ * b.scan("Depts")
+ * .project(
+ * b.field("deptno")
+ * b.multisetQuery(b2 ->
+ * b2.scan("Emps")
+ * .build()))
+ * }</pre>
+ *
+ * <p>is equivalent to the SQL
+ *
+ * <pre>{@code
+ * SELECT deptno, MULTISET (SELECT * FROM Emps)
+ * FROM Depts
+ * }</pre> */
+ @Experimental
+ public RexSubQuery multisetQuery(Function<RelBuilder, RelNode> f) {
+ return RexSubQuery.multiset(f.apply(this));
+ }
+
+ /** Creates a MAP sub-query.
+ *
+ * <p>For example,
+ *
+ * <pre>{@code
+ * b.scan("Depts")
+ * .project(
+ * b.field("deptno")
+ * b.multisetQuery(b2 ->
+ * b2.scan("Emps")
+ * .project(b2.field("empno"), b2.field("job"))
+ * .build()))
+ * }</pre>
+ *
+ * <p>is equivalent to the SQL
+ *
+ * <pre>{@code
+ * SELECT deptno, MAP (SELECT empno, job FROM Emps)
+ * FROM Depts
+ * }</pre> */
+ @Experimental
+ public RexSubQuery mapQuery(Function<RelBuilder, RelNode> f) {
+ return RexSubQuery.map(f.apply(this));
+ }
+
/** Creates an AND. */
public RexNode and(RexNode... operands) {
return and(ImmutableList.copyOf(operands));
diff --git a/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java b/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
index bdfe0c7..c210874 100644
--- a/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
+++ b/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
@@ -2609,6 +2609,68 @@
assertThat(f.apply(createBuilder()), hasTree(expected));
}
+ @Test void testArrayQuery() {
+ // Equivalent SQL:
+ // SELECT deptno, ARRAY (SELECT * FROM Emp)
+ // FROM Dept AS d
+ final Function<RelBuilder, RelNode> f = b ->
+ b.scan("DEPT")
+ .project(
+ b.field("DEPTNO"),
+ b.arrayQuery(b2 ->
+ b2.scan("EMP")
+ .build()))
+ .build();
+
+ final String expected = "LogicalProject(DEPTNO=[$0], $f1=[ARRAY({\n"
+ + "LogicalTableScan(table=[[scott, EMP]])\n"
+ + "})])\n"
+ + " LogicalTableScan(table=[[scott, DEPT]])\n";
+ assertThat(f.apply(createBuilder()), hasTree(expected));
+ }
+
+ @Test void testMultisetQuery() {
+ // Equivalent SQL:
+ // SELECT deptno, MULTISET (SELECT * FROM Emp)
+ // FROM Dept AS d
+ final Function<RelBuilder, RelNode> f = b ->
+ b.scan("DEPT")
+ .project(
+ b.field("DEPTNO"),
+ b.multisetQuery(b2 ->
+ b2.scan("EMP")
+ .build()))
+ .build();
+
+ final String expected = "LogicalProject(DEPTNO=[$0], $f1=[MULTISET({\n"
+ + "LogicalTableScan(table=[[scott, EMP]])\n"
+ + "})])\n"
+ + " LogicalTableScan(table=[[scott, DEPT]])\n";
+ assertThat(f.apply(createBuilder()), hasTree(expected));
+ }
+
+ @Test void testMapQuery() {
+ // Equivalent SQL:
+ // SELECT deptno, MAP (SELECT empno, job FROM Emp)
+ // FROM Dept AS d
+ final Function<RelBuilder, RelNode> f = b ->
+ b.scan("DEPT")
+ .project(
+ b.field("DEPTNO"),
+ b.mapQuery(b2 ->
+ b2.scan("EMP")
+ .project(b2.field("EMPNO"), b2.field("JOB"))
+ .build()))
+ .build();
+
+ final String expected = "LogicalProject(DEPTNO=[$0], $f1=[MAP({\n"
+ + "LogicalProject(EMPNO=[$0], JOB=[$2])\n"
+ + " LogicalTableScan(table=[[scott, EMP]])\n"
+ + "})])\n"
+ + " LogicalTableScan(table=[[scott, DEPT]])\n";
+ assertThat(f.apply(createBuilder()), hasTree(expected));
+ }
+
@Test void testAlias() {
// Equivalent SQL:
// SELECT *
diff --git a/site/_docs/algebra.md b/site/_docs/algebra.md
index 7a97140..66b2792 100644
--- a/site/_docs/algebra.md
+++ b/site/_docs/algebra.md
@@ -448,6 +448,9 @@
The following methods convert a sub-query into a scalar value (a `BOOLEAN` in
the case of `in`, `exists`, `some`, `all`, `unique`;
any scalar type for `scalarQuery`).
+an `ARRAY` for `arrayQuery`,
+a `MAP` for `mapQuery`,
+and a `MULTISET` for `multisetQuery`).
In all the following, `relFn` is a function that takes a `RelBuilder` argument
and returns a `RelNode`. You typically implement it as a lambda; the method
@@ -457,8 +460,11 @@
| Method | Description
|:------------------- |:-----------
| `all(expr, op, relFn)` | Returns whether *expr* has a particular relation to all of the values of the sub-query
+| `arrayQuery(relFn)` | Returns the rows of a sub-query as an `ARRAY`
| `exists(relFn)` | Tests whether sub-query is non-empty
| `in(expr, relFn)`<br/>`in(exprList, relFn)` | Tests whether a value occurs in a sub-query
+| `mapQuery(relFn)` | Returns the rows of a sub-query as a `MAP`
+| `multisetQuery(relFn)` | Returns the rows of a sub-query as a `MULTISET`
| `scalarQuery(relFn)` | Returns the value of the sole column of the sole row of a sub-query
| `some(expr, op, relFn)` | Returns whether *expr* has a particular relation to one or more of the values of the sub-query
| `unique(relFn)` | Returns whether the rows of a sub-query are unique
