Postgres`on conflict`更新变量而不是表，语法错误在“

Question

我创建了一个插入一系列唯一代码的postgres查询。如果一个代码是重复的，我运行以下代码。

在约束uniquecode上发生冲突时不做任何操作；

ON CONFLICT ON CONSTRAINT uniquecode DO UPDATE SET "created_at" = NOW();

    PERFORM * FROM (
      SELECT c."created_at"
      FROM "codes" as c
      ORDER BY "created_at" DESC
      LIMIT 1
    ) AS "newest";
    IF ("newest"::xmax::text::int > 0) THEN
      "counter" = "counter" - 1;
    END IF;

Answer 1

您可以使用：

ON CONFLICT ON CONSTRAINT uniquecode
DO UPDATE SET count = youtable.column - 1