diff --git a/apps/desktop/src/components/editor/QueryEditor.vue b/apps/desktop/src/components/editor/QueryEditor.vue
index 03bf01c212..ddcb248147 100644
--- a/apps/desktop/src/components/editor/QueryEditor.vue
+++ b/apps/desktop/src/components/editor/QueryEditor.vue
@@ -80,7 +80,7 @@ import {
   sqlObjectNavigationTypeFromCompletionObjectType,
   type SqlObjectNavigationTarget,
 } from "@/lib/sql/sqlNavigation";
-import { buildHoverTableSql, ddlForHoverPreview, hoverTableMatchesScope, quoteIdentifier, quoteQualifiedName, reformatHoverDdl, scopeHoverTables, type HoverTableScope } from "@/lib/editor/hoverTableSql";
+import { buildHoverTableSql, ddlForHoverPreview, hoverTableMatchesScope, normalizeAlignedSqlWhitespace, quoteIdentifier, quoteQualifiedName, reformatHoverDdl, scopeHoverTables, type HoverTableScope } from "@/lib/editor/hoverTableSql";
 import { constrainSqlHoverLayout } from "@/lib/editor/sqlHoverLayout";
 import { lineColumnToOffset, sqlErrorDecorationRange as resolveSqlErrorDecorationRange } from "@/lib/sql/sqlDiagnostics";
 import {
@@ -2331,6 +2331,7 @@ function createHoverDom(title: string, detail: string, sqlContent?: string, rows
   dom.appendChild(detailNode);
 
   let layoutController: ReturnType<typeof constrainSqlHoverLayout> | null = null;
+  let handleCopy: ((event: ClipboardEvent) => void) | null = null;
 
   if (sqlContent) {
     const separator = document.createElement("div");
@@ -2351,6 +2352,24 @@ function createHoverDom(title: string, detail: string, sqlContent?: string, rows
     // 返回 mount/destroy 给 CodeMirror TooltipView 生命周期钩子，
     // 避免 MutationObserver 监听 body 全子树来兜底清理。
     layoutController = constrainSqlHoverLayout(dom, sqlContainer);
+
+    // The tooltip pads column names/types with literal spaces so they line up
+    // visually (see alignColumnRows). Selecting that text and copying it via
+    // the native OS/browser copy carries those spaces verbatim, which shows
+    // up as long literal space runs when pasted into a plain-text editor.
+    // Normalize just the clipboard payload so the on-screen alignment is
+    // untouched but paste targets get clean single-spaced SQL.
+    handleCopy = (event: ClipboardEvent) => {
+      const selection = document.getSelection();
+      if (!selection || selection.isCollapsed) return;
+      if (!dom.contains(selection.anchorNode) && !dom.contains(selection.focusNode)) return;
+      const text = selection.toString();
+      if (text !== sqlContent) return;
+      const normalized = normalizeAlignedSqlWhitespace(text);
+      if (normalized === text) return;
+      event.clipboardData?.setData("text/plain", normalized);
+      event.preventDefault();
+    };
   }
 
   for (const row of rows) {
@@ -2362,8 +2381,20 @@ function createHoverDom(title: string, detail: string, sqlContent?: string, rows
 
   return {
     dom,
-    mount: layoutController ? () => layoutController?.mount() : undefined,
-    destroy: layoutController ? () => layoutController?.destroy() : undefined,
+    mount:
+      layoutController || handleCopy
+        ? () => {
+            layoutController?.mount();
+            if (handleCopy) document.addEventListener("copy", handleCopy);
+          }
+        : undefined,
+    destroy:
+      layoutController || handleCopy
+        ? () => {
+            layoutController?.destroy();
+            if (handleCopy) document.removeEventListener("copy", handleCopy);
+          }
+        : undefined,
   };
 }
 
diff --git a/apps/desktop/src/lib/editor/__tests__/hoverTableSql.spec.ts b/apps/desktop/src/lib/editor/__tests__/hoverTableSql.spec.ts
index 7eb2834c31..cbc709d6c8 100644
--- a/apps/desktop/src/lib/editor/__tests__/hoverTableSql.spec.ts
+++ b/apps/desktop/src/lib/editor/__tests__/hoverTableSql.spec.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { buildHoverTableSql, ddlForHoverPreview, hoverTableMatchesScope, reformatHoverDdl, sanitizeHoverDdl, scopeHoverTables } from "@/lib/editor/hoverTableSql";
+import { buildHoverTableSql, ddlForHoverPreview, hoverTableMatchesScope, normalizeAlignedSqlWhitespace, reformatHoverDdl, sanitizeHoverDdl, scopeHoverTables } from "@/lib/editor/hoverTableSql";
 import type { ColumnInfo, IndexInfo } from "@/types/database";
 
 type ColumnOverride = Partial<ColumnInfo> & { name: string; data_type: string };
@@ -327,3 +327,35 @@ describe("hover table scope", () => {
     expect(hoverTableMatchesScope({ name: "orders" }, { database: "sales", schema: "public" })).toBe(false);
   });
 });
+
+describe("normalizeAlignedSqlWhitespace", () => {
+  it("collapses column-alignment padding to single spaces", () => {
+    const aligned = '    "id"         integer default nextval(\'x\'::regclass) not null,\n    "username"   character varying(255) not null,';
+    expect(normalizeAlignedSqlWhitespace(aligned)).toBe('    "id" integer default nextval(\'x\'::regclass) not null,\n    "username" character varying(255) not null,');
+  });
+
+  it("preserves each line's leading indentation", () => {
+    expect(normalizeAlignedSqlWhitespace('  primary key ("id")')).toBe('  primary key ("id")');
+  });
+
+  it("leaves single-spaced text unchanged", () => {
+    const text = "create table t (a int);";
+    expect(normalizeAlignedSqlWhitespace(text)).toBe(text);
+  });
+
+  it("preserves semantic whitespace in literals, identifiers, and comments", () => {
+    const aligned = `create table t (
+    "display  name" varchar(20) default 'a  b' not null, -- keep  this
+    [comment  text]  varchar(20) comment 'first  second',
+    escaped         varchar(20) default 'it\\'s  spaced',
+    body            text default $$x  y$$ /* keep  that */
+);`;
+
+    expect(normalizeAlignedSqlWhitespace(aligned)).toBe(`create table t (
+    "display  name" varchar(20) default 'a  b' not null, -- keep  this
+    [comment  text] varchar(20) comment 'first  second',
+    escaped varchar(20) default 'it\\'s  spaced',
+    body text default $$x  y$$ /* keep  that */
+);`);
+  });
+});
diff --git a/apps/desktop/src/lib/editor/hoverTableSql.ts b/apps/desktop/src/lib/editor/hoverTableSql.ts
index 8cf92153e9..b051488902 100644
--- a/apps/desktop/src/lib/editor/hoverTableSql.ts
+++ b/apps/desktop/src/lib/editor/hoverTableSql.ts
@@ -155,6 +155,135 @@ function alignColumnRows(rows: ColumnFieldParts[]): string[] {
   });
 }
 
+/**
+ * Collapse column-alignment padding outside SQL literals and comments, keeping
+ * each line's leading indentation intact. The hover tooltip renders padding for
+ * readability, but copied SQL must preserve semantic whitespace inside values.
+ */
+export function normalizeAlignedSqlWhitespace(text: string): string {
+  let result = "";
+  let index = 0;
+  let lineStart = true;
+  let blockComment = false;
+  let dollarQuoteEnd = "";
+
+  while (index < text.length) {
+    if (blockComment) {
+      const end = text.indexOf("*/", index);
+      if (end === -1) return result + text.slice(index);
+      result += text.slice(index, end + 2);
+      lineStart = text[end + 1] === "\n";
+      index = end + 2;
+      blockComment = false;
+      continue;
+    }
+
+    if (dollarQuoteEnd) {
+      const end = text.indexOf(dollarQuoteEnd, index);
+      if (end === -1) return result + text.slice(index);
+      result += text.slice(index, end + dollarQuoteEnd.length);
+      lineStart = false;
+      index = end + dollarQuoteEnd.length;
+      dollarQuoteEnd = "";
+      continue;
+    }
+
+    const char = text[index];
+    const next = text[index + 1];
+
+    if (char === "\n" || char === "\r") {
+      result += char;
+      index += 1;
+      lineStart = true;
+      continue;
+    }
+
+    if (lineStart && (char === " " || char === "\t")) {
+      result += char;
+      index += 1;
+      continue;
+    }
+    lineStart = false;
+
+    if (char === "-" && next === "-") {
+      const end = text.indexOf("\n", index);
+      if (end === -1) return result + text.slice(index);
+      result += text.slice(index, end);
+      index = end;
+      continue;
+    }
+
+    if (char === "/" && next === "*") {
+      result += "/*";
+      index += 2;
+      blockComment = true;
+      continue;
+    }
+
+    if (char === "$" && (index === 0 || !/[\w$]/.test(text[index - 1]))) {
+      const match = /^\$[A-Za-z_][A-Za-z0-9_]*\$|^\$\$/.exec(text.slice(index));
+      if (match) {
+        result += match[0];
+        index += match[0].length;
+        dollarQuoteEnd = match[0];
+        continue;
+      }
+    }
+
+    if (char === "'" || char === '"' || char === "`") {
+      const quote = char;
+      const start = index;
+      index += 1;
+      while (index < text.length) {
+        if (text[index] === quote) {
+          if (text[index + 1] === quote) index += 2;
+          else {
+            index += 1;
+            break;
+          }
+        } else if (text[index] === "\\" && index + 1 < text.length) {
+          index += 2;
+        } else {
+          index += 1;
+        }
+      }
+      result += text.slice(start, index);
+      continue;
+    }
+
+    if (char === "[") {
+      const start = index;
+      index += 1;
+      while (index < text.length) {
+        if (text[index] === "]") {
+          if (text[index + 1] === "]") index += 2;
+          else {
+            index += 1;
+            break;
+          }
+        } else {
+          index += 1;
+        }
+      }
+      result += text.slice(start, index);
+      continue;
+    }
+
+    if (char === " ") {
+      let end = index + 1;
+      while (text[end] === " ") end += 1;
+      result += " ";
+      index = end;
+      continue;
+    }
+
+    result += char;
+    index += 1;
+  }
+
+  return result;
+}
+
 /**
  * Quote a SQL identifier by wrapping it in double quotes with proper escaping.
  */