PostgreSQL 9.2.2。表“xxx”有一个条目，但不能从这部分查询中引用

Question

当我尝试在 Postgresql 9.2.2 中执行下一个查询时收到错误消息。

SELECT emp_wallet_periods.employer_id, t.ttl as total, COALESCE(t.imported,0), COALESCE(t.spend, 0), COALESCE(t.available, 0), emp_wallet_periods.year, emp_wallet_periods.month
    FROM (
        SELECT employer_id,
            CAST (date_part('month', to_timestamp(date_created)) AS INTEGER) as month,
            CAST (date_part('year', to_timestamp(date_created)) AS INTEGER) as year
        FROM z_employer_wallet
        WHERE state = 1
        GROUP BY 1, 2, 3) as emp_wallet_periods
    INNER JOIN get_employers_availability_by_month(emp_wallet_periods.employer_id, emp_wallet_periods.year, emp_wallet_periods.month) as t ON t.employerId = emp_wallet_periods.employer_id
    ORDER BY emp_wallet_periods.year DESC, t.available DESC, emp_wallet_periods.month DESC

同样的查询在 Postgresql 9.5.6 中完美运行。

我收到的确切错误消息是：

错误：对表的 FROM 子句条目的引用无效 “emp_wallet_periods”第 9 行：内部联接 get_employers_availability_by_month(emp_wallet_p...

^ 提示：表“emp_wallet_periods”有一个条目，但不能 从查询的这一部分引用。

我想念什么？

Answer 1

不幸的是，这种语法在 Postgres 9.2 中不可用。 FROM 子句子查询和函数调用的 LATERAL 选项在 Postgres 9.3. 中引入

Answer 2

语法是T1 { [INNER] | { LEFT | RIGHT | FULL } [OUTER] } JOIN T2 ON boolean_expression https://www.postgresql.org/docs/9.2/static/queries-table-expressions.html

如您所见，您不能在 JOIN 中使用函数

...get_employers_availability_by_month(emp_wallet_periods.employer_id, emp_wallet_periods.year, emp_wallet_periods.month) as t...

你可以做的是SELECT get_employers_availability_by_month(emp_wallet_periods.employer_id, emp_wallet_periods.year, emp_wallet_periods.month) FROM original_query

并加入结果。

Answer 3

SELECT emp_wallet_periods.employer_id, t.ttl as total, COALESCE(t.imported,0), COALESCE(t.spend, 0), COALESCE(t.available, 0), emp_wallet_periods.year, emp_wallet_periods.month
    FROM (
        SELECT employer_id,
            CAST (date_part('month', to_timestamp(date_created)) AS INTEGER) as month,
            CAST (date_part('year', to_timestamp(date_created)) AS INTEGER) as year
        FROM z_employer_wallet
        WHERE state = 1
        GROUP BY 1, 2, 3) as emp_wallet_periods
    INNER JOIN (SELECT get_employers_availability_by_month(emp_wallet_periods.employer_id, emp_wallet_periods.year, emp_wallet_periods.month)
                FROM (SELECT employer_id,
                            CAST (date_part('month', to_timestamp(date_created)) AS INTEGER) as month,
                            CAST (date_part('year', to_timestamp(date_created)) AS INTEGER) as year
                        FROM z_employer_wallet
                        WHERE state = 1
                        GROUP BY 1, 2, 3) as emp_wallet_periods) as t 
    ON t.employerId = emp_wallet_periods.employer_id
    ORDER BY emp_wallet_periods.year DESC, t.available DESC, emp_wallet_periods.month DESC

Answer 4

这是我的完整原始函数 get_employers_availability_by_month();

CREATE OR REPLACE FUNCTION get_employers_availability_by_month(eid integer, y integer, m integer)
RETURNS TABLE(employerId integer, ttl real, imported real, spend real, available real, year integer, month integer) AS $$
BEGIN
    RETURN QUERY
    SELECT emp_wallet.employer_id, SUM(emp_wallet.total) as total, emp_wallet_imported.imported, emp_wallet_spend.spend, CASE WHEN (emp_wallet_spend.spend > 0 AND emp_wallet_imported.imported is null) THEN CAST((0 - emp_wallet_spend.spend) as real)
        WHEN emp_wallet_spend.spend > 0 THEN (emp_wallet_imported.imported-emp_wallet_spend.spend)
        ELSE emp_wallet_imported.imported END AS availability, CAST(date_part('year', to_timestamp(emp_wallet.date_created)) as INTEGER) as year, CAST(date_part('month', to_timestamp(emp_wallet.date_created)) as INTEGER) as month
    FROM z_employer_wallet as emp_wallet
    LEFT JOIN (
        SELECT employer_id, SUM(total) AS imported
            FROM z_employer_wallet as emp_wal
            WHERE emp_wal.total > 0
                AND emp_wal.flow = 1
                AND emp_wal.state = 1
                AND emp_wal.employer_id = eid
                AND date_part('year', to_timestamp(emp_wal.date_created)) = y
                AND date_part('month', to_timestamp(emp_wal.date_created)) = m
            GROUP BY employer_id
        ) as emp_wallet_imported ON emp_wallet_imported.employer_id = emp_wallet.employer_id
    LEFT JOIN (
        SELECT employer_id, SUM(total) AS spend
            FROM z_employer_wallet as emp_wal
            WHERE emp_wal.total > 0
                AND emp_wal.flow = 2
                AND emp_wal.state = 1
                AND emp_wal.employer_id = eid
                AND date_part('month', to_timestamp(emp_wal.date_created)) = m
                AND date_part('year', to_timestamp(emp_wal.date_created)) = y
            GROUP BY employer_id
    ) as emp_wallet_spend ON emp_wallet_spend.employer_id = emp_wallet.employer_id
    WHERE emp_wallet.employer_id = eid
        AND date_part('month', to_timestamp(emp_wallet.date_created)) = m
        AND date_part('year', to_timestamp(emp_wallet.date_created)) = y
    GROUP BY emp_wallet.employer_id, emp_wallet_imported.imported, emp_wallet_spend.spend, date_part('month', to_timestamp(emp_wallet.date_created)), date_part('year', to_timestamp(emp_wallet.date_created))
    ORDER BY emp_wallet.employer_id DESC;
RETURN;
END
$$
LANGUAGE plpgsql;