聊聊flink Table的Set Operations

序
本文主要研究一下flink Table的Set Operations
实例
Union
Table left = tableEnv.fromDataSet(ds1, “a, b, c”);
Table right = tableEnv.fromDataSet(ds2, “a, b, c”);
Table result = left.union(right);
union方法类似sql的union
UnionAll
Table left = tableEnv.fromDataSet(ds1, “a, b, c”);
Table right = tableEnv.fromDataSet(ds2, “a, b, c”);
Table result = left.unionAll(right);
unionAll方法类似sql的union all
Intersect
Table left = tableEnv.fromDataSet(ds1, “a, b, c”);
Table right = tableEnv.fromDataSet(ds2, “d, e, f”);
Table result = left.intersect(right);
intersect方法类似sql的intersect
IntersectAll
Table left = tableEnv.fromDataSet(ds1, “a, b, c”);
Table right = tableEnv.fromDataSet(ds2, “d, e, f”);
Table result = left.intersectAll(right);
intersectAll方法类似sql的intersect all
Minus
Table left = tableEnv.fromDataSet(ds1, “a, b, c”);
Table right = tableEnv.fromDataSet(ds2, “a, b, c”);
Table result = left.minus(right);
minus方法类似sql的except
MinusAll
Table left = tableEnv.fromDataSet(ds1, “a, b, c”);
Table right = tableEnv.fromDataSet(ds2, “a, b, c”);
Table result = left.minusAll(right);
minusAll方法类似sql的except all
In
Table left = ds1.toTable(tableEnv, “a, b, c”);
Table right = ds2.toTable(tableEnv, “a”);

// using implicit registration
Table result = left.select(“a, b, c”).where(“a.in(” + right + “)”);

// using explicit registration
tableEnv.registerTable(“RightTable”, right);
Table result = left.select(“a, b, c”).where(“a.in(RightTable)”);
in方法类似sql的in
Table
flink-table_2.11-1.7.0-sources.jar!/org/apache/flink/table/api/table.scala
class Table(
private[flink] val tableEnv: TableEnvironment,
private[flink] val logicalPlan: LogicalNode) {

//……

def union(right: Table): Table = {
// check that right table belongs to the same TableEnvironment
if (right.tableEnv != this.tableEnv) {
throw new ValidationException(“Only tables from the same TableEnvironment can be unioned.”)
}
new Table(tableEnv, Union(logicalPlan, right.logicalPlan, all = false).validate(tableEnv))
}

def unionAll(right: Table): Table = {
// check that right table belongs to the same TableEnvironment
if (right.tableEnv != this.tableEnv) {
throw new ValidationException(“Only tables from the same TableEnvironment can be unioned.”)
}
new Table(tableEnv, Union(logicalPlan, right.logicalPlan, all = true).validate(tableEnv))
}

def intersect(right: Table): Table = {
// check that right table belongs to the same TableEnvironment
if (right.tableEnv != this.tableEnv) {
throw new ValidationException(
“Only tables from the same TableEnvironment can be intersected.”)
}
new Table(tableEnv, Intersect(logicalPlan, right.logicalPlan, all = false).validate(tableEnv))
}

def intersectAll(right: Table): Table = {
// check that right table belongs to the same TableEnvironment
if (right.tableEnv != this.tableEnv) {
throw new ValidationException(
“Only tables from the same TableEnvironment can be intersected.”)
}
new Table(tableEnv, Intersect(logicalPlan, right.logicalPlan, all = true).validate(tableEnv))
}

def minus(right: Table): Table = {
// check that right table belongs to the same TableEnvironment
if (right.tableEnv != this.tableEnv) {
throw new ValidationException(“Only tables from the same TableEnvironment can be ” +
“subtracted.”)
}
new Table(tableEnv, Minus(logicalPlan, right.logicalPlan, all = false)
.validate(tableEnv))
}

def minusAll(right: Table): Table = {
// check that right table belongs to the same TableEnvironment
if (right.tableEnv != this.tableEnv) {
throw new ValidationException(“Only tables from the same TableEnvironment can be ” +
“subtracted.”)
}
new Table(tableEnv, Minus(logicalPlan, right.logicalPlan, all = true)
.validate(tableEnv))
}

//……
}
union及unionAll使用的是Union，intersect及intersectAll使用的是Intersect，minus及minusAll使用的是Minus
Union
flink-table_2.11-1.7.0-sources.jar!/org/apache/flink/table/plan/logical/operators.scala
case class Union(left: LogicalNode, right: LogicalNode, all: Boolean) extends BinaryNode {
override def output: Seq[Attribute] = left.output

override protected[logical] def construct(relBuilder: RelBuilder): RelBuilder = {
left.construct(relBuilder)
right.construct(relBuilder)
relBuilder.union(all)
}

override def validate(tableEnv: TableEnvironment): LogicalNode = {
if (tableEnv.isInstanceOf[StreamTableEnvironment] && !all) {
failValidation(s”Union on stream tables is currently not supported.”)
}

val resolvedUnion = super.validate(tableEnv).asInstanceOf[Union]
if (left.output.length != right.output.length) {
failValidation(s”Union two tables of different column sizes:” +
s” ${left.output.size} and ${right.output.size}”)
}
val sameSchema = left.output.zip(right.output).forall { case (l, r) =>
l.resultType == r.resultType
}
if (!sameSchema) {
failValidation(s”Union two tables of different schema:” +
s” [${left.output.map(a => (a.name, a.resultType)).mkString(“, “)}] and” +
s” [${right.output.map(a => (a.name, a.resultType)).mkString(“, “)}]”)
}
resolvedUnion
}
}
Union继承了BinaryNode，其construct方法通过relBuilder.union来构建union操作
Intersect
flink-table_2.11-1.7.0-sources.jar!/org/apache/flink/table/plan/logical/operators.scala
case class Intersect(left: LogicalNode, right: LogicalNode, all: Boolean) extends BinaryNode {
override def output: Seq[Attribute] = left.output

override protected[logical] def construct(relBuilder: RelBuilder): RelBuilder = {
left.construct(relBuilder)
right.construct(relBuilder)
relBuilder.intersect(all)
}

override def validate(tableEnv: TableEnvironment): LogicalNode = {
if (tableEnv.isInstanceOf[StreamTableEnvironment]) {
failValidation(s”Intersect on stream tables is currently not supported.”)
}

val resolvedIntersect = super.validate(tableEnv).asInstanceOf[Intersect]
if (left.output.length != right.output.length) {
failValidation(s”Intersect two tables of different column sizes:” +
s” ${left.output.size} and ${right.output.size}”)
}
// allow different column names between tables
val sameSchema = left.output.zip(right.output).forall { case (l, r) =>
l.resultType == r.resultType
}
if (!sameSchema) {
failValidation(s”Intersect two tables of different schema:” +
s” [${left.output.map(a => (a.name, a.resultType)).mkString(“, “)}] and” +
s” [${right.output.map(a => (a.name, a.resultType)).mkString(“, “)}]”)
}
resolvedIntersect
}
}
Intersect继承了BinaryNode，其construct方法通过relBuilder.intersect来构建intersect操作
Minus
flink-table_2.11-1.7.0-sources.jar!/org/apache/flink/table/plan/logical/operators.scala
case class Minus(left: LogicalNode, right: LogicalNode, all: Boolean) extends BinaryNode {
override def output: Seq[Attribute] = left.output

override protected[logical] def construct(relBuilder: RelBuilder): RelBuilder = {
left.construct(relBuilder)
right.construct(relBuilder)
relBuilder.minus(all)
}

override def validate(tableEnv: TableEnvironment): LogicalNode = {
if (tableEnv.isInstanceOf[StreamTableEnvironment]) {
failValidation(s”Minus on stream tables is currently not supported.”)
}

val resolvedMinus = super.validate(tableEnv).asInstanceOf[Minus]
if (left.output.length != right.output.length) {
failValidation(s”Minus two table of different column sizes:” +
s” ${left.output.size} and ${right.output.size}”)
}
val sameSchema = left.output.zip(right.output).forall { case (l, r) =>
l.resultType == r.resultType
}
if (!sameSchema) {
failValidation(s”Minus two table of different schema:” +
s” [${left.output.map(a => (a.name, a.resultType)).mkString(“, “)}] and” +
s” [${right.output.map(a => (a.name, a.resultType)).mkString(“, “)}]”)
}
resolvedMinus
}
}
Minus继承了BinaryNode，其construct方法通过relBuilder.minus来构建minus操作
小结

Table对Set提供了union、unionAll、intersect、intersectAll、minus、minusAll、in(in在where子句中)操作
union及unionAll使用的是Union，intersect及intersectAll使用的是Intersect，minus及minusAll使用的是Minus
Union继承了BinaryNode，其construct方法通过relBuilder.union来构建union操作；Intersect继承了BinaryNode，其construct方法通过relBuilder.intersect来构建intersect操作；Minus继承了BinaryNode，其construct方法通过relBuilder.minus来构建minus操作

doc
Set Operations