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Wiki / SQLSTATE

42701 — 重复列（duplicate_column）

同一定义中重复指定了同名列。

英文手册覆盖始于 PostgreSQL 8.1. 来源历史与运行验证各自保留独立版本边界。

当前阅读 PG 18·选择有来源记录的版本

8.18.28.38.49.09.19.29.39.49.59.61011121314151617181920
aliases
未知
class name
Syntax Error or Access Rule Violation
condition name
duplicate_column
lang
en
sqlstate
42701

版本定义 PG 18

42701 — 重复列

速览 {#at-a-glance}

SQLSTATE 42701 是 Class 42 中的 duplicate_column。42701 表示重复列。选定的 CREATE TABLE 路径两次列出 id，在创建修正后的不同列之前报告 column "%s" specified more than once。

含义 {#meaning}

42701 表示重复列。在处理表定义时，PostgreSQL 会先比较本地 ColumnDef 名称，再合并继承属性。因此在一个定义中两次列出同名列会在创建修复表前报告 ERROR：column "%s" specified more than once。这个本地名称检查不同于继承默认值、类型或排序规则冲突；后者可能使用其他 SQLSTATE。

诊断 {#diagnosis}

检查展开后的生成列列表，包括带引号标识符，以及拼接到同一个 CREATE TABLE 中的迁移片段。PostgreSQL 在普通名称处理后比较标识符，因此意外重复的未引用名称仍然是同一列名。选定 DDL 的 ERROR 后自动提交会话仍为 IDLE；显式 BEGIN 中同样的错误会让事务进入 INERROR，必须 ROLLBACK 或回滚到合适保存点后再重试。要把它与 42611 的继承默认值冲突，以及继承列合并时的类型/排序规则错误区分开。

处理 {#response}

删除重复定义或给它一个有意的不同名称，重新执行完整 DDL，并检查最终目录。如果重复来自已经执行过的迁移，先比较现有表定义，再决定使用 ALTER TABLE 还是新的 CREATE TABLE；不要假设失败的 CREATE TABLE 留下了半成品关系。选定修复创建 id 和 payload 两列并确认列数。

报文 {#messages}

选定的 tablecmds.c 分支以明确的 ERROR 发出主报文 column "%s" specified more than once；%s 是重复列名。相邻源码分支可能为继承类型/排序规则冲突发出其他 SQLSTATE。只有客户端异常而没有服务器 SQLSTATE 和主报文时，不能据此认定 42701。

代表案例 {#case}

本页使用与运行器注册表相同的语句。执行时，syntax_schema、syntax_role 等生成名称会替换为一次性实例中的实际值。

CREATE TABLE syntax_schema.duplicate_table (id integer, id text);
CREATE TABLE syntax_schema.repaired_table (id integer, payload text);
SELECT count(*) FROM information_schema.columns WHERE table_schema = 'syntax_schema_name' AND table_name = 'repaired_table_name';

选定的 18.6 运行记录结构化诊断并通过修复断言；10.21 运行通过同一案例的具体检查。可下载的案例和证据投影分别是 42701 案例 JSON 和 作者证据。运行器清单为 verify/cases/42701/cases.json，页面 SQL 会与共享注册表核对。

版本 {#versions}

选定的自然运行范围是 PostgreSQL 18.6 与 10.21，不能据此推断所有中间版本的行为。

相关 {#related}

来源 {#sources}

  • src.errcodes.18.6 — fixed errcodes.txt definition at commit 724edf9bde9d356724ad384a2e196edc3c9f80f7; SHA-256 6e8de346643ba84aa3c9c6a73360acfc7b2dfb89162c06c08ce9bf5bcd5bbcba (source).
  • src.duplicate-column.18.6 — src/backend/commands/tablecmds.c at REL_18_6 commit 724edf9bde9d356724ad384a2e196edc3c9f80f7; fixed blob SHA-256 422dc8e833df4940755973c757e338295822ba3e4c7266c40669f49f96eb15a9 (source).
  • src.duplicate-column.10.23 — src/backend/commands/tablecmds.c at REL_10_23 commit 02991e79f8f58bc208f05dcc8af0c62dbe0a6ea4; fixed blob SHA-256 6de441c88496c6cf57a836898388085ec08bf69afd70d07acdafd6089b9b5f8c (source).
  • src.calls.REL_18_6 / src.calls.REL_10_23 — fixed call scans, SHA-256 9ee8a0e81d8f0825c5c1ae45583439859a26e602bdd4ce2f2a62aa278867ccbf / 00d16d3eb01b71ccf1b245c8f3102f9d0ec9f36fb02777b8dd1b99fcb263040c.

比较版本

SQLSTATE 证据与已记录的运行版本

cases · duplicate_column
{
  "assertions": [
    "SQLSTATE is 42701 with the duplicate-column diagnostic",
    "The session remains IDLE",
    "A table with distinct columns can be created and inspected"
  ],
  "case_id": "duplicate_column",
  "cleanup": "Drop the case schema with an owner connection.",
  "has_snippet": true,
  "position": 0,
  "preconditions": [
    "A runner-owned disposable target is provisioned."
  ],
  "repair": "Give each column a distinct name and rerun the DDL.",
  "trigger": "Create a table that lists id twice.",
  "versions": [
    "10",
    "18"
  ]
}
claims · identity.class-and-condition
{
  "claim_id": "identity.class-and-condition",
  "limits": "Directory identity does not identify every backend path.",
  "method": "Read fixed errcodes.txt and the locked catalogue metadata.",
  "position": 0,
  "runtime": [],
  "sources": [
    "src.errcodes.18.6"
  ],
  "statement": "42701 is the duplicate_column condition in Class 42."
}
claims · mechanism.backend-path
{
  "claim_id": "mechanism.backend-path",
  "limits": "Other calls can use the same SQLSTATE with different context or dynamic fields.",
  "method": "Trace the resolved REL_18_6 and REL_10_23 source call records at the locked commits.",
  "position": 1,
  "runtime": [],
  "sources": [
    "src.duplicate-column.18.6",
    "src.duplicate-column.10.23"
  ],
  "statement": "The fixed source calls for 42701 include the mechanism and message boundary selected for this page."
}
claims · runtime.representative-case
{
  "claim_id": "runtime.representative-case",
  "limits": "This covers the selected case and targets only; it does not generalize to all drivers or intermediate releases.",
  "method": "Run the shared registry case and inspect structured diagnostics, state/recovery assertions, and cleanup.",
  "position": 2,
  "runtime": [
    "runtime.42701-syntax-latest2.latest",
    "runtime.42701-syntax-pg10.pg10"
  ],
  "sources": [
    "manifest.42701",
    "snippet-registry.42701"
  ],
  "statement": "The selected duplicate_column case passed on isolated PostgreSQL 18.6 and 10.21 targets."
}
claims · versions.catalogue-boundary
{
  "claim_id": "versions.catalogue-boundary",
  "limits": "Definition presence is not an exact behavioral introduction.",
  "method": "Read generated facts and selected summaries.",
  "position": 3,
  "runtime": [],
  "sources": [
    "src.errcodes.18.6",
    "src.calls.REL_18_6",
    "src.calls.REL_10_23"
  ],
  "statement": "The locked catalogue records 42701; runtime scope is limited to the selected targets."
}
messages · message.duplicate-column
{
  "limits": "",
  "message_id": "message.duplicate-column",
  "path": "",
  "position": 0,
  "raw": {
    "id": "message.duplicate-column",
    "primary_template": "column \"%s\" specified more than once",
    "severity_source": "explicit ERROR",
    "sources": [
      "src.duplicate-column.18.6",
      "src.duplicate-column.10.23"
    ],
    "sqlstate": "42701"
  },
  "severity": "explicit ERROR",
  "sources": [
    "src.duplicate-column.18.6",
    "src.duplicate-column.10.23"
  ],
  "templates": [
    {
      "kind": "primary",
      "literal": "column \" \" specified more than once",
      "position": 0,
      "role": "",
      "template": "column \"%s\" specified more than once"
    }
  ]
}
runtimes · runtime.42701-syntax-latest2.latest · 18.6 (Homebrew) · passed
{
  "cases": [],
  "limits": "",
  "position": 0,
  "raw": {
    "assertions": [
      {
        "expected": "42701",
        "name": "42701 SQLSTATE",
        "observed": "42701",
        "passed": true
      },
      {
        "expected": "ERROR",
        "name": "42701 ERROR severity",
        "observed": "ERROR",
        "passed": true
      },
      {
        "expected": "column \"id\" specified more than once",
        "name": "42701 primary diagnostic",
        "observed": "column \"id\" specified more than once",
        "passed": true
      },
      {
        "expected": "IDLE",
        "name": "duplicate-column error leaves session usable",
        "observed": "IDLE",
        "passed": true
      },
      {
        "expected": {
          "columns": 2,
          "status": "IDLE"
        },
        "name": "unique column definitions repair table",
        "observed": {
          "columns": 2,
          "status": "IDLE"
        },
        "passed": true
      }
    ],
    "case_manifest": {
      "id": "manifest.42701",
      "kind": "local_artifact",
      "path": "verify/cases/42701/cases.json",
      "sha256": "9f792ba437d56c9c8517dcc45582799d04c83a50180b5e290e8cc3b90c93fd7e",
      "source_role": "case_manifest"
    },
    "cleanup": {
      "errors": [],
      "passed": true
    },
    "environment": {
      "TimeZone": "Asia/Shanghai",
      "backend_pid": 2968,
      "binary": {
        "bindir": "/opt/homebrew/Cellar/postgresql@18/18.6/bin",
        "pg_config": "/opt/homebrew/bin/pg_config",
        "pg_config_version": "PostgreSQL 18.6 (Homebrew)",
        "postgres": "/opt/homebrew/Cellar/postgresql@18/18.6/bin/postgres"
      },
      "connection_scope": "runner-owned localhost port",
      "current_user": "runner",
      "docker": {},
      "lc_messages": "C",
      "libpq_version": "18.6",
      "locale": "en_US.UTF-8",
      "log_destination": "csvlog,jsonlog",
      "log_error_verbosity": "verbose",
      "log_min_error_statement": "error",
      "log_min_messages": "error",
      "logging_collector": "on",
      "machine": "arm64",
      "max_connections": "100",
      "platform": "macOS-26.6.2-arm64-arm-64bit-Mach-O",
      "psycopg_version": "3.3.5",
      "python_version": "3.14.6 (main, Jun 10 2026, 10:03:53) [Clang 21.0.0 (clang-2100.0.123.102)]",
      "server_encoding": "UTF8",
      "server_version": "18.6 (Homebrew)",
      "server_version_num": "180006",
      "target_kind": "latest",
      "wal_level": "logical"
    },
    "id": "runtime.42701-syntax-latest2.latest",
    "observed": {
      "column_count": 2,
      "connection_autocommit": true,
      "diagnostic": {
        "column_name": null,
        "constraint_name": null,
        "context": null,
        "datatype_name": null,
        "exception_type": "DuplicateColumn",
        "internal_position": null,
        "internal_query": null,
        "message_detail": null,
        "message_hint": null,
        "message_primary": "column \"id\" specified more than once",
        "schema_name": null,
        "severity": "ERROR",
        "severity_nonlocalized": "ERROR",
        "source_file": "tablecmds.c",
        "source_function": "MergeAttributes",
        "source_line": "2639",
        "sqlstate": "42701",
        "statement_position": null,
        "table_name": null,
        "text": "column \"id\" specified more than once"
      },
      "failed_status": "IDLE",
      "repair_status": "IDLE"
    },
    "raw": "verify/results/42701-syntax-latest2/latest/raw.jsonl",
    "raw_sha256": "50b147ec604b0ebf828d1d31065262eb4a3dfba432b44b03a2bae2b54d02df3a",
    "run_id": "42701-syntax-latest2",
    "server_version": "18.6 (Homebrew)",
    "server_version_num": 180006,
    "snippet_registry": {
      "id": "snippet-registry.42701",
      "kind": "local_artifact",
      "path": "verify/cases/42701/snippets.json",
      "sha256": "20767b2140a3242ce7450b1c3eaf0dc89b87f75fd18055d9220c8aeb2df5400f",
      "source_role": "snippet_registry"
    },
    "status": "passed",
    "summary": "verify/results/42701-syntax-latest2/latest/summary.json",
    "summary_sha256": "23dfe97f3c9373be57b80a6c2d86c3f8ba5467998a158fd5fb44dc4dbf6c1b73",
    "target": "latest"
  },
  "run_id": "42701-syntax-latest2",
  "runtime_id": "runtime.42701-syntax-latest2.latest",
  "server_version": "18.6 (Homebrew)",
  "status": "passed",
  "target": "latest"
}
runtimes · runtime.42701-syntax-pg10.pg10 · 10.21 (Debian 10.21-1.pgdg90+1) · passed
{
  "cases": [],
  "limits": "",
  "position": 1,
  "raw": {
    "assertions": [
      {
        "expected": "42701",
        "name": "42701 SQLSTATE",
        "observed": "42701",
        "passed": true
      },
      {
        "expected": "ERROR",
        "name": "42701 ERROR severity",
        "observed": "ERROR",
        "passed": true
      },
      {
        "expected": "column \"id\" specified more than once",
        "name": "42701 primary diagnostic",
        "observed": "column \"id\" specified more than once",
        "passed": true
      },
      {
        "expected": "IDLE",
        "name": "duplicate-column error leaves session usable",
        "observed": "IDLE",
        "passed": true
      },
      {
        "expected": {
          "columns": 2,
          "status": "IDLE"
        },
        "name": "unique column definitions repair table",
        "observed": {
          "columns": 2,
          "status": "IDLE"
        },
        "passed": true
      }
    ],
    "case_manifest": {
      "id": "manifest.42701",
      "kind": "local_artifact",
      "path": "verify/cases/42701/cases.json",
      "sha256": "9f792ba437d56c9c8517dcc45582799d04c83a50180b5e290e8cc3b90c93fd7e",
      "source_role": "case_manifest"
    },
    "cleanup": {
      "errors": [],
      "passed": true
    },
    "environment": {
      "TimeZone": "Etc/UTC",
      "backend_pid": 80,
      "binary": {},
      "connection_scope": "runner-owned localhost port",
      "current_user": "postgres",
      "docker": {
        "architecture": "arm64",
        "command": "/usr/local/bin/docker",
        "digest": "sha256:b2baf8998630663d21370da06387c950e587071bdd307ee34e661cdcc7442bcc",
        "id": "sha256:b2baf8998630663d21370da06387c950e587071bdd307ee34e661cdcc7442bcc",
        "image": "postgres:10",
        "image_created": "2022-06-23T09:11:18.374607054Z",
        "image_ref": "postgres@sha256:b2baf8998630663d21370da06387c950e587071bdd307ee34e661cdcc7442bcc",
        "log_destination": "csvlog",
        "os": "linux",
        "repo_digests": [
          "postgres@sha256:b2baf8998630663d21370da06387c950e587071bdd307ee34e661cdcc7442bcc"
        ]
      },
      "lc_messages": "en_US.utf8",
      "libpq_version": "18.6",
      "locale": "en_US.UTF-8",
      "log_destination": "csvlog",
      "log_error_verbosity": "verbose",
      "log_min_error_statement": "error",
      "log_min_messages": "error",
      "logging_collector": "on",
      "machine": "arm64",
      "max_connections": "100",
      "platform": "macOS-26.6.2-arm64-arm-64bit-Mach-O",
      "psycopg_version": "3.3.5",
      "python_version": "3.14.6 (main, Jun 10 2026, 10:03:53) [Clang 21.0.0 (clang-2100.0.123.102)]",
      "server_encoding": "UTF8",
      "server_version": "10.21 (Debian 10.21-1.pgdg90+1)",
      "server_version_num": "100021",
      "target_kind": "pg10",
      "wal_level": "logical"
    },
    "id": "runtime.42701-syntax-pg10.pg10",
    "observed": {
      "column_count": 2,
      "connection_autocommit": true,
      "diagnostic": {
        "column_name": null,
        "constraint_name": null,
        "context": null,
        "datatype_name": null,
        "exception_type": "DuplicateColumn",
        "internal_position": null,
        "internal_query": null,
        "message_detail": null,
        "message_hint": null,
        "message_primary": "column \"id\" specified more than once",
        "schema_name": null,
        "severity": "ERROR",
        "severity_nonlocalized": "ERROR",
        "source_file": "tablecmds.c",
        "source_function": "MergeAttributes",
        "source_line": "1744",
        "sqlstate": "42701",
        "statement_position": null,
        "table_name": null,
        "text": "column \"id\" specified more than once"
      },
      "failed_status": "IDLE",
      "repair_status": "IDLE"
    },
    "raw": "verify/results/42701-syntax-pg10/pg10/raw.jsonl",
    "raw_sha256": "df7ce42bcd46bac5e7e750222372f9b45ea0da1b0e97da258828b484e0ba0856",
    "run_id": "42701-syntax-pg10",
    "server_version": "10.21 (Debian 10.21-1.pgdg90+1)",
    "server_version_num": 100021,
    "snippet_registry": {
      "id": "snippet-registry.42701",
      "kind": "local_artifact",
      "path": "verify/cases/42701/snippets.json",
      "sha256": "20767b2140a3242ce7450b1c3eaf0dc89b87f75fd18055d9220c8aeb2df5400f",
      "source_role": "snippet_registry"
    },
    "status": "passed",
    "summary": "verify/results/42701-syntax-pg10/pg10/summary.json",
    "summary_sha256": "e8485e813c64d48c0a8aaabea9e3844e2aaa28b2817f1ee04362e4a85d48213b",
    "target": "pg10"
  },
  "run_id": "42701-syntax-pg10",
  "runtime_id": "runtime.42701-syntax-pg10.pg10",
  "server_version": "10.21 (Debian 10.21-1.pgdg90+1)",
  "status": "passed",
  "target": "pg10"
}
sources · src.errcodes.18.6
{
  "commit": "724edf9bde9d356724ad384a2e196edc3c9f80f7",
  "docs_url": "",
  "kind": "upstream_source",
  "location": "",
  "path": "src/backend/utils/errcodes.txt",
  "position": 0,
  "sha256": "6e8de346643ba84aa3c9c6a73360acfc7b2dfb89162c06c08ce9bf5bcd5bbcba",
  "source_id": "src.errcodes.18.6",
  "tag": "REL_18_6",
  "url": "https://github.com/postgres/postgres/blob/724edf9bde9d356724ad384a2e196edc3c9f80f7/src/backend/utils/errcodes.txt"
}
sources · src.calls.REL_18_6
{
  "commit": "",
  "docs_url": "",
  "kind": "local_artifact",
  "location": "",
  "path": "raw/calls/REL_18_6.jsonl",
  "position": 1,
  "sha256": "9ee8a0e81d8f0825c5c1ae45583439859a26e602bdd4ce2f2a62aa278867ccbf",
  "source_id": "src.calls.REL_18_6",
  "tag": "",
  "url": ""
}
sources · src.calls.REL_10_23
{
  "commit": "",
  "docs_url": "",
  "kind": "local_artifact",
  "location": "",
  "path": "raw/calls/REL_10_23.jsonl",
  "position": 2,
  "sha256": "00d16d3eb01b71ccf1b245c8f3102f9d0ec9f36fb02777b8dd1b99fcb263040c",
  "source_id": "src.calls.REL_10_23",
  "tag": "",
  "url": ""
}
sources · src.duplicate-column.18.6
{
  "commit": "724edf9bde9d356724ad384a2e196edc3c9f80f7",
  "docs_url": "",
  "kind": "upstream_source",
  "location": "",
  "path": "src/backend/commands/tablecmds.c",
  "position": 3,
  "sha256": "422dc8e833df4940755973c757e338295822ba3e4c7266c40669f49f96eb15a9",
  "source_id": "src.duplicate-column.18.6",
  "tag": "REL_18_6",
  "url": "https://github.com/postgres/postgres/blob/724edf9bde9d356724ad384a2e196edc3c9f80f7/src/backend/commands/tablecmds.c#L2636-L2639"
}
sources · src.duplicate-column.10.23
{
  "commit": "02991e79f8f58bc208f05dcc8af0c62dbe0a6ea4",
  "docs_url": "",
  "kind": "upstream_source",
  "location": "",
  "path": "src/backend/commands/tablecmds.c",
  "position": 4,
  "sha256": "6de441c88496c6cf57a836898388085ec08bf69afd70d07acdafd6089b9b5f8c",
  "source_id": "src.duplicate-column.10.23",
  "tag": "REL_10_23",
  "url": "https://github.com/postgres/postgres/blob/02991e79f8f58bc208f05dcc8af0c62dbe0a6ea4/src/backend/commands/tablecmds.c#L1741-L1744"
}
sources · manifest.42701
{
  "commit": "",
  "docs_url": "",
  "kind": "local_artifact",
  "location": "",
  "path": "verify/cases/42701/cases.json",
  "position": 5,
  "sha256": "9f792ba437d56c9c8517dcc45582799d04c83a50180b5e290e8cc3b90c93fd7e",
  "source_id": "manifest.42701",
  "tag": "",
  "url": ""
}
sources · snippet-registry.42701
{
  "commit": "",
  "docs_url": "",
  "kind": "local_artifact",
  "location": "",
  "path": "verify/cases/42701/snippets.json",
  "position": 6,
  "sha256": "20767b2140a3242ce7450b1c3eaf0dc89b87f75fd18055d9220c8aeb2df5400f",
  "source_id": "snippet-registry.42701",
  "tag": "",
  "url": ""
}

来源引用

完整定义与证据 JSON

定义来源

center · PostgreSQL 18 · english-manuals:c0eaa7afeafb3917f33f6ff61d59734c95369ab88388943d930cdfdd20ebe093

正文语言: zh-Hans · english-manuals:c0eaa7afeafb3917f33f6ff61d59734c95369ab88388943d930cdfdd20ebe093