查询 table，同时排除其他 table 中引用的值

Question

我有一个数据库，里面装满了来自不同银行账户的交易。每笔交易都带有 user_id、bank_id、account_id 和 transaction_id。如果用户选择忽略银行、帐户或个人交易，我想在查询时排除交易。

换句话说，如果用户：

忽略银行，跳过与该银行的所有交易bank_id，
忽略一个帐户，与该帐户的所有交易都会被跳过，account_id，
忽略单个交易，跳过 transaction_id 的交易。

我当前的数据库是这样的：

-- Simplified for brevity.
CREATE TABLE IF NOT EXISTS transactions
(
    user_id        TEXT NOT NULL,
    transaction_id TEXT NOT NULL,
    account_id     TEXT NOT NULL,
    bank_id        TEXT NOT NULL,
    PRIMARY KEY (user_id, transaction_id)
);

-- Exclusion tables for banks and accounts are similar.
CREATE TABLE IF NOT EXISTS excluded_transactions
(
    id             INTEGER PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
    user_id        TEXT NOT NULL,
    transaction_id TEXT NOT NULL
);

CREATE INDEX IF NOT EXISTS exc_trn_idx ON excluded_transactions (user_id, transaction_id);

只要用户 abc 排除银行、账户或交易，它就会被添加到适当的排除项中 table。然后查询如下所示：

WITH b AS (
  SELECT bank_id FROM excluded_banks WHERE user_id = 'abc'
), a AS (
  SELECT account_id FROM excluded_accounts WHERE user_id = 'abc'
), t AS (
  SELECT transaction_id FROM excluded_transactions WHERE user_id = 'abc'
)
SELECT * FROM transactions 
WHERE user_id = 'abc'
AND bank_id NOT IN (SELECT * FROM b) 
AND account_id NOT IN (SELECT * FROM a)
AND transaction_id NOT IN (SELECT * FROM t)

这在约 1M 事务的测试集上给出了 OK 性能（平均约 100 毫秒的计划时间，约 1 秒的执行时间）。但是，我担心它会随着数据库的增长而显着降低。

我的问题是：我如何改进tables/queries以有效地检索具有上述约束的交易？较慢的写入是 acceptable 如果它们使读取更快。另外，如果我采用的一般方法不是最优的，请告诉我 and/or 建议改进方法。

Answer 1

我建议这样写：

SELECT t.*
FROM transactions t
WHERE t.user_id = 'abc' AND
      NOT EXISTS (SELECT 1
                  FROM excluded_banks eb
                  WHERE eb.bank_id = t.bank_id AND
                        eb.user_id = t.user_id
                 ) AND
      NOT EXISTS (SELECT 1
                  FROM excluded_accounts ea
                  WHERE ea.account_id = t.account_id AND
                        ea.user_id = t.user_id
                 ) AND
      NOT EXISTS (SELECT 1
                  FROM excluded_transaction et
                  WHERE et.transaction_id = t.transaction_id AND
                        et.user_id = t.user_id
                 );

然后确保您有以下索引：

excluded_banks(user_id, bank_id)
excluded_accounts(user_id, account_id)
excluded_transaction(user_id, transaction_id)

查询 table，同时排除其他 table 中引用的值

Query a table while excluding values referenced in other tables

sql

database

postgresql

performance

query-performance