Union

Descrição

Mescla os documentos de outro pipeline com os do pipeline atual.

Sintaxe

Node.js

const results = await db.pipeline()
  .collection("cities/SF/restaurants")
  .union(db.pipeline().collection("cities/NYC/restaurants"))
  .execute();

Exemplos de clientes

Node.js
  const results = await db.pipeline()
    .collection("cities/SF/restaurants")
    .where(eq("type", "chinese"))
    .union(db.pipeline()
      .collection("cities/NYC/restaurants")
      .where(eq("type", "italian")))
    .where(gte("rating", 4.5))
    .execute();

Web

const results = await execute(db.pipeline()
  .collection("cities/SF/restaurants")
  .where(field("type").equal("Chinese"))
  .union(db.pipeline()
    .collection("cities/NY/restaurants")
    .where(field("type").equal("Italian")))
  .where(field("rating").greaterThanOrEqual(4.5))
  .sort(field("__name__").descending())
);
test.firestore.js
Swift
let results = try await db.pipeline()
  .collection("cities/SF/restaurants")
  .where(Field("type").equal("Chinese"))
  .union(with: db.pipeline()
    .collection("cities/NY/restaurants")
    .where(Field("type").equal("Italian")))
  .where(Field("rating").greaterThanOrEqual(4.5))
  .sort([Field("__name__").descending()])
  .execute()
PipelineSnippets.swift

Kotlin

val results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute()
DocSnippets.kt

Java

Task<Pipeline.Snapshot> results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

results = (
    client.pipeline()
    .collection("cities/SF/restaurants")
    .where(Field.of("type").equal("Chinese"))
    .union(
        client.pipeline()
        .collection("cities/NY/restaurants")
        .where(Field.of("type").equal("Italian"))
    )
    .where(Field.of("rating").greater_than_or_equal(4.5))
    .sort(Field.of("__name__").descending())
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot results =
    firestore
        .pipeline()
        .collection("cities/SF/restaurants")
        .where(field("type").equal("Chinese"))
        .union(
            firestore
                .pipeline()
                .collection("cities/NY/restaurants")
                .where(field("type").equal("Italian")))
        .where(field("rating").greaterThanOrEqual(4.5))
        .sort(descending(field("__name__")))
        .execute()
        .get();
PipelineSnippets.java

Comportamento

Essa etapa executa vários pipelines em paralelo e concatena os resultados.

Ordem não determinista dos resultados

A ordem em que os resultados são combinados entre os dois pipelines não é determinista. Qualquer ordem percebida é instável e não deve ser confiável. Uma etapa sort pode ser adicionada se for necessária uma ordem estável.

Node.js
  const results = await db.pipeline()
    .collection("cities/SF/restaurants")
    .where(eq("type", "chinese"))
    .union(db.pipeline()
      .collection("cities/NYC/restaurants")
      .where(eq("type", "italian")))
    .where(gte("rating", 4.5))
    .sort(Field.of("__name__"))
    .execute();

Kotlin

val results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute()
DocSnippets.kt

Java

Task<Pipeline.Snapshot> results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

results = (
    client.pipeline()
    .collection("cities/SF/restaurants")
    .where(Field.of("type").equal("Chinese"))
    .union(
        client.pipeline()
        .collection("cities/NY/restaurants")
        .where(Field.of("type").equal("Italian"))
    )
    .where(Field.of("rating").greater_than_or_equal(4.5))
    .sort(Field.of("__name__").descending())
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot results =
    firestore
        .pipeline()
        .collection("cities/SF/restaurants")
        .where(field("type").equal("Chinese"))
        .union(
            firestore
                .pipeline()
                .collection("cities/NY/restaurants")
                .where(field("type").equal("Italian")))
        .where(field("rating").greaterThanOrEqual(4.5))
        .sort(descending(field("__name__")))
        .execute()
        .get();
PipelineSnippets.java

Resultados duplicados

A etapa union não remove resultados duplicados. Uma etapa distinct ou aggregate pode ser adicionada se for necessário remover resultados duplicados.