Sql 在查询中重用分区上的和返回值

我正在寻找一种方法，以避免在查询中执行两次计算，如：

SELECT DISTINCT
    coins.price_btc,
    coins.price_eur,
    coins.price_usd,
    coins.currency_name,
    coins.currency_symbol,
    SUM ( market_transactions.quantity ) OVER ( PARTITION BY market_transactions.market_coin_id ) * coins.price_eur AS holdings_eur,
    SUM ( market_transactions.quantity ) OVER ( PARTITION BY market_transactions.market_coin_id ) * coins.price_usd AS holdings_usd,
    SUM ( market_transactions.quantity ) OVER ( PARTITION BY market_transactions.market_coin_id ) * coins.price_btc AS holdings_btc,
    SUM ( market_transactions.quantity ) OVER ( PARTITION BY market_transactions.market_coin_id ) AS holdings 
FROM
    market_transactions
    INNER JOIN coins ON coins.id = market_transactions.market_coin_id 
WHERE
    market_transactions.user_id = 1 
ORDER BY
    coins.currency_symbol

我不确定分区上的总和是否一直在运行

感谢您的指点，我相信查询也可以优化，但我不确定从哪里开始

CREATE TABLE "public"."coins" (
  "id" int8 NOT NULL DEFAULT nextval('coins_id_seq'::regclass),
  "currency_symbol" text COLLATE "pg_catalog"."default" NOT NULL DEFAULT NULL,
  "currency_name" text COLLATE "pg_catalog"."default" NOT NULL DEFAULT NULL,
  "price_usd" numeric(16,7) NOT NULL DEFAULT NULL,
  "price_eur" numeric(16,7) NOT NULL DEFAULT NULL,
  "price_btc" numeric(16,7) NOT NULL DEFAULT NULL,
  CONSTRAINT "coins_pkey" PRIMARY KEY ("id")
)

CREATE TABLE "public"."market_transactions" (
  "id" int8 NOT NULL DEFAULT nextval('market_transactions_id_seq'::regclass),
  "user_id" int4 NOT NULL DEFAULT NULL,
  "quantity" numeric(18,8) NOT NULL DEFAULT NULL,
  "market_coin_id" int4 DEFAULT NULL,
  CONSTRAINT "market_transactions_pkey" PRIMARY KEY ("id")
)

一个用户有许多涉及硬币的交易（

market\u transactions.market\u coin\u id

是

coins.id

），我试图对每一笔交易的拥有量（

market\u transactions.quantity

）求和，然后将该值乘以以不同货币表示的硬币价格（btc、欧元、美元）

对查询运行解释（即解释选择不同…），查看查询计划是什么。最有可能的是，它只运行了一次窗口函数。如果要多次运行，请尝试添加外部选择：

SELECT DISTINCT 
  price_btc, 
  price_eur, 
  price_usd, 
  currency_name,
  currency_symbol,
  holdings * price_eur AS holdings_eur,
  holdings * price_usd AS holdings_usd,
  holdings * price_btc AS holdings_btc,
  holdings
FROM (
    SELECT
    coins.price_btc,
    coins.price_eur,
    coins.price_usd,
    coins.currency_name,
    coins.currency_symbol,
    SUM ( market_transactions.quantity ) OVER ( PARTITION BY market_transactions.market_coin_id ) AS holdings 
FROM
    market_transactions
    INNER JOIN coins ON coins.id = market_transactions.market_coin_id 
WHERE
    market_transactions.user_id = 1 
) src
ORDER BY
    currency_symbol

对查询运行解释（即解释选择不同…），查看查询计划是什么。最有可能的是，它只运行了一次窗口函数。如果要多次运行，请尝试添加外部选择：

SELECT DISTINCT 
  price_btc, 
  price_eur, 
  price_usd, 
  currency_name,
  currency_symbol,
  holdings * price_eur AS holdings_eur,
  holdings * price_usd AS holdings_usd,
  holdings * price_btc AS holdings_btc,
  holdings
FROM (
    SELECT
    coins.price_btc,
    coins.price_eur,
    coins.price_usd,
    coins.currency_name,
    coins.currency_symbol,
    SUM ( market_transactions.quantity ) OVER ( PARTITION BY market_transactions.market_coin_id ) AS holdings 
FROM
    market_transactions
    INNER JOIN coins ON coins.id = market_transactions.market_coin_id 
WHERE
    market_transactions.user_id = 1 
) src
ORDER BY
    currency_symbol

---

我建议在加入之前进行聚合，然后执行以下操作：

SELECT c.*,
       mt.quantity * c.price_eur AS holdings_eur,
       mt.quantity * c.price_usd AS holdings_usd,
       mt.quantity * c.price_btc AS holdings_btc,
       mt.quantity * c.market_coin_id AS holdings 
FROM coins c JOIN
     (SELECT mt.market_coin_id, SUM(mt.quantity) as quantity
      FROM market_transactions t
      WHERE mt.user_id = 1 
      GROUP BY mt.market_coin_id
     ) mt
     ON c.id = mt.market_coin_id 
ORDER BY c.currency_symbol

---

我建议在加入之前进行聚合，然后执行以下操作：

SELECT c.*,
       mt.quantity * c.price_eur AS holdings_eur,
       mt.quantity * c.price_usd AS holdings_usd,
       mt.quantity * c.price_btc AS holdings_btc,
       mt.quantity * c.market_coin_id AS holdings 
FROM coins c JOIN
     (SELECT mt.market_coin_id, SUM(mt.quantity) as quantity
      FROM market_transactions t
      WHERE mt.user_id = 1 
      GROUP BY mt.market_coin_id
     ) mt
     ON c.id = mt.market_coin_id 
ORDER BY c.currency_symbol

---

请共享表结构、示例数据、预期输出以及查询试图生成的结果的说明。作为一般的经验法则，每当我看到SELECT DISTINCT和Window函数时，我都怀疑查询的逻辑正确性。感谢检查，我添加了简化的表结构，这需要我进行一些插入，但应该很容易。请共享表结构、示例数据、，预期输出和查询试图生成的结果的说明。作为一般的经验法则，每当我看到SELECT DISTINCT和Window函数时，我都会怀疑查询的逻辑正确性。感谢您的检查，我添加了简化的表结构，这会让我花一点时间进行插入，但应该很容易。