postgresql - "CONSTRAINT"处或附近的语法错误 PostgreSQL

Question

我正在尝试创建一个新表，但在下面的语句中一直在“CONSTRAINT”处或附近出现语法错误。我已经确保在我声明的最后一列之后有一个 ,，它是 Tags，就在 CONSTRAINT 行的正上方。有谁知道为什么会这样？声明约束的所有在线示例似乎都涉及 CREATE TABLE 语句，而不是 CREATE TABLE AS 语句。那有关系吗？感谢您的帮助!

顺便说一句，下面的约束行是从我已经创建的表中复制/粘贴的，该表使用了 CREATE TABLE 语句，而不是 CREATE TABLE AS 语句，这就是为什么我问约束是否不适用于 CREATE TABLE AS 语句。

CREATE TABLE "2017Projects" AS
SELECT
    "STAGING_PROJECTS"."_PROJECT_NUMBER", 
    "STAGING_PROJECTS"."_PROJECT_DESCRIPTION",
    "STAGING_PROJECTS"."_PROJECT_STATUS",
    "STAGING_PROJECTS"."_TEMPLATE_FLAG",
    "STAGING_PROJECTS"."_PROJECT_START_DATE",
    "STAGING_PROJECTS"."_PROJECT_COMPLETION_DATE",
    "STAGING_PROJECTS"."_COMPANY",
    "STAGING_PROJECTS"."_LOCATION_NUMBER",
    "STAGING_TASKS"."_PARENT_TASK_NUMBER",
    "STAGING_TASKS"."_PARENT_TASK_DESCRIPTION",
    "STAGING_TASKS"."_TASK_NUMBER",
    "STAGING_TASKS"."_TASK_DESCRIPTION",
    "STAGING_TASKS"."_TASK_START_DATE",
    "STAGING_TASKS"."_TASK_COMPLETION_DATE",
    "STAGING_TASKS"."_EBS_ACCOUNT",
    "STAGING_TASKS"."_FUSION_ACCOUNT",
    CASE
        WHEN left("STAGING_PROJECTS"."_PROJECT_NUMBER",2) = 'C0' THEN 
            '('||"STAGING_PROJECTS"."_PROJECT_NUMBER"||') '||"STAGING_PROJECTS"."_PROJECT_DESCRIPTION"
        ELSE
            "STAGING_PROJECTS"."_PROJECT_DESCRIPTION"
    END AS "Project",
    '('||"STAGING_TASKS"."_TASK_NUMBER"||') '||"STAGING_TASKS"."_TASK_DESCRIPTION" AS "Task",
    NULL AS "Investment_Priority",
    NULL AS "Class",
    NULL AS "Tags",

    --ERROR ON NEXT LINE HERE!!!
    CONSTRAINT "2017Projects_pk" PRIMARY KEY ("_PROJECT_NUMBER", "_TASK_NUMBER")
FROM
    "STAGING_PROJECTS";

Answer 1

您需要使用第二条语句添加约束:

CREATE TABLE "2017Projects" AS
SELECT
    "STAGING_PROJECTS"."_PROJECT_NUMBER", 
    ...,
    NULL AS "Tags"
FROM
    "STAGING_PROJECTS";

ALTER TABLE "2017Projects" ADD CONSTRAINT "2017Projects_pk"
    PRIMARY KEY ("_PROJECT_NUMBER", "_TASK_NUMBER")

CREATE TABLE 和 ALTER TABLE 语句应该在单个事务中运行。

请浏览this great Stack DBA article ，@a_horse_with_no_name 作为贡献者。