Unnest 可以在 PostgreSQL 中过滤吗？

Question

我有一个 table 的值，其中“TAHUN”列按 date_part('year'::text, insert_date) 分组，值为 1000在“TAHUN”列中总计

我想像这样将行转置为列（但“TAHUN”列保持动态，因此我不必在年终时手动插入它）：

我对使用 unnest 按列“TAHUN”进行过滤感到困惑。这是我的查询：

SELECT
    unnest(array['PENDAPATAN', 'PENJUALAN 1', 'PENJUALAN 2', 'PENDAPATAN LAIN-LAIN', 'TOTAL PENDAPATAN', 'HARGA POKOK PENJUALAN (HPP)', 'PEMBELIAN', 'ONGKOS KIRIM']) AS "title",
    unnest(array["PENDAPATAN", "PENJUALAN 1", "PENJUALAN 2", "PENDAPATAN LAIN-LAIN", "TOTAL PENDAPATAN", "HARGA POKOK PENJUALAN (HPP)", "PEMBELIAN", "ONGKOS KIRIM"]) FILTER (WHERE "TAHUN" != 1000) AS "dynamic year",
    unnest(array["PENDAPATAN", "PENJUALAN 1", "PENJUALAN 2", "PENDAPATAN LAIN-LAIN", "TOTAL PENDAPATAN", "HARGA POKOK PENJUALAN (HPP)", "PEMBELIAN", "ONGKOS KIRIM"]) FILTER (WHERE "TAHUN" = 1000) AS "total"
FROM vw_blm_dashboard_hasil_usaha
GROUP BY "title", "dynamic year", "total";

unnest可以过滤吗？或者您还有其他方法可以解决这个问题吗？

先致谢

Answer 1

您需要将取消嵌套移动到 FROM 子句中，以便获得可以引用的列。

我个人认为使用 VALUES 子句编写此代码更容易阅读：

SELECT
    x.title ,
    max(x.value) FILTER (WHERE v."TAHUN" = 2019) AS "2019",
    max(x.value) FILTER (WHERE v."TAHUN" = 2020) AS "2020",
    max(x.value) FILTER (WHERE v."TAHUN" = 2021) AS "2021",
    max(x.value) FILTER (WHERE v."TAHUN" = 1000) AS "total"
FROM vw_blm_dashboard_hasil_usaha v
 CROSS JOIN LATERAL (  
     values ("PENDAPATAN", 'PENDAPATAN'), 
            ("PENJUALAN 1", 'PENJUALAN 1'), 
            ("PENJUALAN 2", 'PENJUALAN 2'), 
            ... all other columns come here ...
 ) as x(value, title)
GROUP BY x.title;

Unnest 可以在 PostgreSQL 中过滤吗？

Can Unnest filtered in PostgreSQL?

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unnest