table similarity experiment.

src/dynamic/table-similarity.ts

@@ -0,0 +1,51 @@
+import { AnyColumn } from '../util/type-utils.js'
+
+export type TableSimilarity<DB, C extends AnyColumn<DB, keyof DB>> = {
+  TB: SimilarTables<DB, C>
+  DB: DatabaseWithSimilarTables<DB, C>
+}
+
+export type SimilarTables<DB, C extends AnyColumn<DB, keyof DB>> = {
+  [T in keyof DB]: HasEveryColumn<DB, T, C>
+}[keyof DB]
+
+export type HasEveryColumn<DB, TB extends keyof DB, C> = [C] extends [
+  keyof DB[TB],
+]
+  ? TB
+  : never
+
+export type DatabaseWithSimilarTables<
+  DB,
+  C extends AnyColumn<DB, keyof DB>,
+> = Omit<DB, SimilarTables<DB, C>> & {
+  [T in SimilarTables<DB, C>]: Pick<DB[T], keyof DB[SimilarTables<DB, C>]>
+}
+
+export type ScopedTableSimilarity<
+  DB,
+  TB extends keyof DB,
+  C extends AnyColumn<DB, TB>,
+> = {
+  TB: ScopedSimilarTables<DB, TB, C>
+  DB: DatabaseWithScopedSimilarTables<DB, TB, C>
+}
+
+export type ScopedSimilarTables<
+  DB,
+  TB extends keyof DB,
+  C extends AnyColumn<DB, TB>,
+> = {
+  [T in TB]: HasEveryColumn<DB, T, C>
+}[TB]
+
+export type DatabaseWithScopedSimilarTables<
+  DB,
+  TB extends keyof DB,
+  C extends AnyColumn<DB, TB>,
+> = Omit<DB, ScopedSimilarTables<DB, TB, C>> & {
+  [T in ScopedSimilarTables<DB, TB, C>]: Pick<
+    DB[T],
+    keyof DB[ScopedSimilarTables<DB, TB, C>]
+  >
+}

src/index.ts

@@ -60,6 +60,7 @@ export * from './schema/drop-view-builder.js'
 export * from './schema/alter-column-builder.js'
 
 export * from './dynamic/dynamic.js'
+export * from './dynamic/table-similarity.js'
 
 export * from './driver/driver.js'
 export * from './driver/database-connection.js'

test/typings/test-d/table-similarity.test-d.ts

@@ -0,0 +1,35 @@
+import { expectError } from 'tsd'
+import {
+  Expression,
+  expressionBuilder,
+  Kysely,
+  Selectable,
+  SelectQueryBuilder,
+  SelectType,
+  TableSimilarity,
+} from '..'
+import { Database } from '../shared'
+
+async function test(db: Kysely<Database>) {
+  type NameSimilarity = TableSimilarity<Database, 'name'>
+
+  function selectByName<TB extends NameSimilarity['TB']>(
+    table: TB,
+    name: SelectType<NameSimilarity['DB'][TB]['name']>,
+  ): Expression<Selectable<Database[TB]>> {
+    const eb = expressionBuilder<NameSimilarity['DB'], never>()
+
+    return eb
+      .selectFrom(db.dynamic.table<NameSimilarity['TB']>(table).as('t'))
+      .where('t.name', '=', name)
+      .selectAll() as never
+  }
+
+  selectByName('book', "The Hitchhiker's Guide to the Galaxy")
+  selectByName('pet', 'Fido')
+
+  // doesn't have a name column
+  expectError(selectByName('person', 'John Doe'))
+  // name is a string, not a number
+  expectError(selectByName('book', 2))
+}