refactor: move stream and async iterator support from SetBase to Se…

…lect class

…and ensure a proper result type.

src/postgres/query/base/set.ts

@@ -1,8 +1,6 @@
-import { renderQuery } from '../../internal/query'
 import { SetProps } from '../../props/set'
 import { Query } from '../../query'
 import type { Selectable, SelectionSource } from '../../selection'
-import type { QueryStreamConfig } from '../../stream'
 import { orderBy, SortSelection, SortSelector } from '../orderBy'
 
 const kSelectFrom = Symbol()
@@ -41,27 +39,4 @@ export abstract class SetBase<
     self.props.orderBy = orderBy(self.sources, selector)
     return self
   }
-
-  stream(config?: QueryStreamConfig) {
-    const ctx: Query.Context = {
-      query: this as any,
-      values: [],
-      resolvers: [],
-      mutators: [],
-    }
-
-    // TODO: apply mutators to stream
-    const query = renderQuery(ctx)
-    const client = this.db['getClient'](ctx)
-    if (client.stream) {
-      return client.stream(query, ctx.values, config)
-    }
-    throw Error('Streaming not supported by your Postgres client')
-  }
-
-  [Symbol.asyncIterator]() {
-    const stream = this.stream()
-    stream.resume()
-    return stream[Symbol.asyncIterator]()
-  }
 }

src/postgres/query/select.ts

@@ -1,4 +1,7 @@
+import { renderQuery } from '../internal/query'
+import { Query } from '../query'
 import { Selectable, SelectResult, SelectResults } from '../selection'
+import { QueryStream, QueryStreamConfig } from '../stream'
 import { SetType } from '../type'
 import { SelectBase } from './base/select'
 import { Union } from './union'
@@ -14,6 +17,29 @@ export class Select<From extends Selectable[] = any> //
       query: new Union(this.db),
     })
   }
+
+  stream(config?: QueryStreamConfig): QueryStream<SelectResult<From>> {
+    const ctx: Query.Context = {
+      query: this as any,
+      values: [],
+      resolvers: [],
+      mutators: [],
+    }
+
+    // TODO: apply mutators to stream
+    const query = renderQuery(ctx)
+    const client = this.db['getClient'](ctx)
+    if (client.stream) {
+      return client.stream(query, ctx.values, config)
+    }
+    throw Error('Streaming not supported by your Postgres client')
+  }
+
+  [Symbol.asyncIterator](): AsyncIterableIterator<SelectResult<From>> {
+    const stream = this.stream()
+    stream.resume()
+    return stream[Symbol.asyncIterator]()
+  }
 }
 
 export interface Select<From>