diff --git a/src/README.md b/src/README.md
index 3a79d97..0def001 100644
--- a/src/README.md
+++ b/src/README.md
@@ -25,6 +25,8 @@ to communication around the project.
 
 @SQLConfig
 
+@SQLNamespace
+
 @SQLDialect
 
 @SQLDialectSpec
diff --git a/src/complete.ts b/src/complete.ts
index 63595c4..69d5be4 100644
--- a/src/complete.ts
+++ b/src/complete.ts
@@ -3,7 +3,7 @@ import {EditorState, Text} from "@codemirror/state"
 import {syntaxTree} from "@codemirror/language"
 import {SyntaxNode} from "@lezer/common"
 import {Type, Keyword} from "./sql.grammar.terms"
-import {type SQLDialect} from "./sql"
+import {type SQLDialect, SQLNamespace} from "./sql"
 
 function tokenBefore(tree: SyntaxNode) {
   let cursor = tree.cursor().moveTo(tree.from, -1)
@@ -93,23 +93,63 @@ function maybeQuoteCompletions(quote: string | null, completions: readonly Compl
 
 const Span = /^\w*$/, QuotedSpan = /^[`'"]?\w*[`'"]?$/
 
+function isSelfTag(namespace: SQLNamespace): namespace is {self: Completion, children: SQLNamespace} {
+  return (namespace as any).self && typeof (namespace as any).self.label == "string"
+}
+
 class CompletionLevel {
   list: Completion[] = []
   children: {[name: string]: CompletionLevel} | undefined = undefined
 
-  child(name: string, idQuote: string) {
+  constructor(readonly idQuote: string) {}
+
+  child(name: string) {
     let children = this.children || (this.children = Object.create(null))
     let found = children[name]
     if (found) return found
-    if (name) this.list.push(nameCompletion(name, "type", idQuote))
-    return (children[name] = new CompletionLevel)
+    if (name && !this.list.some(c => c.label == name)) this.list.push(nameCompletion(name, "type", this.idQuote))
+    return (children[name] = new CompletionLevel(this.idQuote))
+  }
+
+  maybeChild(name: string) {
+    return this.children ? this.children[name] : null
+  }    
+
+  addCompletion(option: Completion) {
+    let found = this.list.findIndex(o => o.label == option.label)
+    if (found > -1) this.list[found] = option
+    else this.list.push(option)
+  }
+
+  addCompletions(completions: readonly (Completion | string)[]) {
+    for (let option of completions)
+      this.addCompletion(typeof option == "string" ? nameCompletion(option, "property", this.idQuote) : option)
   }
 
-  addCompletions(list: readonly Completion[]) {
-    for (let option of list) {
-      let found = this.list.findIndex(o => o.label == option.label)
-      if (found > -1) this.list[found] = option
-      else this.list.push(option)
+  addNamespace(namespace: SQLNamespace, plainScope: CompletionLevel = this) {
+    if (Array.isArray(namespace)) {
+      this.addCompletions(namespace)
+    } else if (isSelfTag(namespace)) {
+      this.addNamespace(namespace.children)
+    } else {
+      this.addNamespaceObject(namespace as {[name: string]: SQLNamespace}, plainScope)
+    }
+  }
+
+  addNamespaceObject(namespace: {[name: string]: SQLNamespace}, plainScope: CompletionLevel) {
+    for (let name of Object.keys(namespace)) {
+      let children = namespace[name], self: Completion | null = null
+      let parts = name.replace(/\\?\./g, p => p == "." ? "\0" : p).split("\0")
+      let scope = parts.length == 1 ? plainScope : this
+      if (isSelfTag(children)) {
+        self = children.self
+        children = children.children
+      }
+      for (let i = 0; i < parts.length; i++) {
+        if (self && i == parts.length - 1) scope.addCompletion(self)
+        scope = scope.child(parts[i].replace(/\\\./g, "."))
+      }
+      scope.addNamespace(children)
     }
   }
 }
@@ -119,24 +159,22 @@ function nameCompletion(label: string, type: string, idQuote: string): Completio
   return {label, type, apply: idQuote + label + idQuote}
 }
 
-export function completeFromSchema(schema: {[table: string]: readonly (string | Completion)[]},
+// Some of this is more gnarly than it has to be because we're also
+// supporting the deprecated, not-so-well-considered style of
+// supplying the schema (dotted property names for schemas, separate
+// `tables` and `schemas` completions).
+export function completeFromSchema(schema: SQLNamespace,
                                    tables?: readonly Completion[], schemas?: readonly Completion[],
                                    defaultTableName?: string, defaultSchemaName?: string,
                                    dialect?: SQLDialect): CompletionSource {
-  let top = new CompletionLevel
   let idQuote = dialect?.spec.identifierQuotes?.[0] || '"'
-  let defaultSchema = top.child(defaultSchemaName || "", idQuote)
-  for (let table in schema) {
-    let parts = table.replace(/\\?\./g, p => p == "." ? "\0" : p).split("\0")
-    let base = parts.length == 1 ? defaultSchema : top
-    for (let part of parts) base = base.child(part.replace(/\\\./g, "."), idQuote)
-    for (let option of schema[table]) if (option)
-      base.list.push(typeof option == "string" ? nameCompletion(option, "property", idQuote) : option)
-  }
+  let top = new CompletionLevel(idQuote)
+  let defaultSchema = top.child(defaultSchemaName || "")
+  top.addNamespace(schema, defaultSchema)
   if (tables) defaultSchema.addCompletions(tables)
   if (schemas) top.addCompletions(schemas)
   top.addCompletions(defaultSchema.list)
-  if (defaultTableName) top.addCompletions(defaultSchema.child(defaultTableName, idQuote).list)
+  if (defaultTableName) top.addCompletions(defaultSchema.child(defaultTableName).list)
 
   return (context: CompletionContext) => {
     let {parents, from, quoted, empty, aliases} = sourceContext(context.state, context.pos)
@@ -146,10 +184,12 @@ export function completeFromSchema(schema: {[table: string]: readonly (string |
     for (let name of parents) {
       while (!level.children || !level.children[name]) {
         if (level == top) level = defaultSchema
-        else if (level == defaultSchema && defaultTableName) level = level.child(defaultTableName, idQuote)
+        else if (level == defaultSchema && defaultTableName) level = level.child(defaultTableName)
         else return null
       }
-      level = level.child(name, idQuote)
+      let next = level.maybeChild(name)
+      if (!next) return null
+      level = next
     }
     let quoteAfter = quoted && context.state.sliceDoc(context.pos, context.pos + 1) == quoted
     let options = level.list
diff --git a/src/sql.ts b/src/sql.ts
index 49ff047..8707fc0 100644
--- a/src/sql.ts
+++ b/src/sql.ts
@@ -115,23 +115,27 @@ export class SQLDialect {
   }
 }
 
+/// The type used to describe a level of the schema for
+/// [completion](#lang-sql.SQLConfig.schema). Can be an array of
+/// options (columns), an object mapping table or schema names to
+/// deeper levels, or a `{self, children}` object that assigns a
+/// completion option to use for its parent property, when the default option
+/// (its name as label and type `"type"`) isn't suitable.
+export type SQLNamespace = {[name: string]: SQLNamespace}
+  | {self: Completion, children: SQLNamespace}
+  | readonly (Completion | string)[]
+
 /// Options used to configure an SQL extension.
 export interface SQLConfig {
   /// The [dialect](#lang-sql.SQLDialect) to use. Defaults to
   /// [`StandardSQL`](#lang-sql.StandardSQL).
   dialect?: SQLDialect,
-  /// An object that maps table names, optionally prefixed with a
-  /// schema name (`"schema.table"`) to options (columns) that can be
-  /// completed for that table. Use lower-case names here.
-  schema?: {[table: string]: readonly (string | Completion)[]},
-  /// By default, the completions for the table names will be
-  /// generated from the `schema` object. But if you want to
-  /// customize them, you can pass an array of completions through
-  /// this option.
+  /// You can use this to define the schemas, tables, and their fields
+  /// for autocompletion.
+  schema?: SQLNamespace,
+  /// @hide
   tables?: readonly Completion[],
-  /// Similar to `tables`, if you want to provide completion objects
-  /// for your schemas rather than using the generated ones, pass them
-  /// here.
+  /// @hide
   schemas?: readonly Completion[],
   /// When given, columns from the named table can be completed
   /// directly at the top level.
diff --git a/test/test-complete.ts b/test/test-complete.ts
index cd68d5f..3562093 100644
--- a/test/test-complete.ts
+++ b/test/test-complete.ts
@@ -174,5 +174,34 @@ describe("SQL completion", () => {
     let s = {schema: {"db\\.conf": ["abc"]}}
     ist(str(get("db|", s)), '"db.conf"')
     ist(str(get('"db.conf".|', s)), "abc")
-  })    
+  })
+
+  it("supports nested schema declarations", () => {
+    let s = {schema: {
+      public: {users: ["email", "id"]},
+      other: {users: ["name", "id"]},
+      plain: ["one", "two"]
+    }}
+    ist(str(get("pl|", s)), "other, plain, public")
+    ist(str(get("plain.|", s)), "one, two")
+    ist(str(get("public.u|", s)), "users")
+    ist(str(get("public.users.e|", s)), "email, id")
+  })
+
+  it("supports self fields to specify table/schema completions", () => {
+    let s: SQLConfig = {schema: {
+      foo: {
+        self: {label: "foo", type: "keyword"},
+        children: {
+          bar: {
+            self: {label: "bar", type: "constant"},
+            children: ["a", "b"]
+          }
+        }
+      }
+    }}
+    ist(get("select f|", s)!.options[0].type, "keyword")
+    ist(get("select foo.|", s)!.options[0].type, "constant")
+    ist(get("select foo.|", s)!.options.length, 1)
+  })
 })