feat: support AS OF queries for CockroachDB

lib/dialect/dialect.ts

@@ -6,6 +6,7 @@ import { AddColumnNode } from '../node/addColumn.js';
 import { AliasNode } from '../node/alias.js';
 import { AlterNode } from '../node/alter.js';
 import { ArrayCallNode } from '../node/arrayCall.js';
+import { AsOfNode } from '../node/asOf.js';
 import { AtNode } from '../node/at.js';
 import { BinaryNode } from '../node/binary.js';
 import { CascadeNode } from '../node/cascade.js';
@@ -208,6 +209,8 @@ export abstract class Dialect<ConfigType> {
                 return this.visitCast(node as CastNode);
             case 'FROM':
                 return this.visitFrom(node as FromNode);
+            case 'AS OF':
+                return this.visitAsOf(node as AsOfNode);
             case 'WHERE':
                 return this.visitWhere(node as WhereNode);
             case 'ORDER BY':
@@ -446,6 +449,10 @@ export abstract class Dialect<ConfigType> {
         }
         return result;
     }
+    public visitAsOf(asOfNode: AsOfNode): string[] {
+        const result = ['AS OF SYSTEM TIME', ...asOfNode.nodes.flatMap(this.visit.bind(this))];
+        return result;
+    }
     public visitWhere(whereNode: WhereNode): string[] {
         this.visitingWhere = true;
         const result = ['WHERE', whereNode.nodes.map(this.visit.bind(this)).join(', ')];

lib/dialect/mssql.ts

@@ -4,6 +4,7 @@
 import assert from 'assert';
 
 import { AlterNode } from '../node/alter.js';
+import { AsOfNode } from '../node/asOf.js';
 import { BinaryNode } from '../node/binary.js';
 import { CaseNode } from '../node/case.js';
 import { ColumnNode } from '../node/column.js';
@@ -47,6 +48,9 @@ export class Mssql extends Dialect<{ questionMarkParameterPlaceholder?: boolean
         }
         return `@${index}`;
     }
+    public visitAsOf(asOfNode: AsOfNode): string[] {
+        throw new Error('Mssql does not support AS OF.');
+    }
     public visitReplace(replaceNode: ReplaceNode): string[] {
         throw new Error('Mssql does not support REPLACE.');
     }

lib/dialect/mysql.ts

@@ -1,6 +1,7 @@
 import assert from 'assert';
 import isNumber from 'lodash/isNumber.js';
 
+import { AsOfNode } from '../node/asOf.js';
 import { BinaryNode } from '../node/binary.js';
 import { ColumnNode } from '../node/column.js';
 import { CreateNode } from '../node/create.js';
@@ -67,6 +68,9 @@ export class Mysql extends Dialect<any> {
         }
         return result;
     }
+    public visitAsOf(asOfNode: AsOfNode): string[] {
+        throw new Error('Mysql does not support AS OF.');
+    }
     public visitOnDuplicate(onDuplicateNode: OnDuplicateNode): string[] {
         const params: string[] = [];
         /* jshint boss: true */

lib/dialect/oracle.ts

@@ -2,6 +2,7 @@ import assert from 'assert';
 
 import { AliasNode } from '../node/alias.js';
 import { AlterNode } from '../node/alter.js';
+import { AsOfNode } from '../node/asOf.js';
 import { BinaryNode } from '../node/binary.js';
 import { CascadeNode } from '../node/cascade.js';
 import { CaseNode } from '../node/case.js';
@@ -95,6 +96,10 @@ export class Oracle extends Dialect<any> {
         }
         return super.visitAlter(alterNode);
     }
+    public visitAsOf(asOfNode: AsOfNode): string[] {
+        const result = ['AS OF TIMESTAMP', ...asOfNode.nodes.flatMap(this.visit.bind(this))];
+        return result;
+    }
     public visitTable(tableNode: TableNode): string[] {
         const table = tableNode.table;
         let txt = '';

lib/dialect/sqlite.ts

@@ -2,6 +2,7 @@ import assert from 'assert';
 import isArray from 'lodash/isArray.js';
 
 import { AddColumnNode } from '../node/addColumn.js';
+import { AsOfNode } from '../node/asOf.js';
 import { BinaryNode } from '../node/binary.js';
 import { CascadeNode } from '../node/cascade.js';
 import { CreateIndexNode } from '../node/createIndex.js';
@@ -48,6 +49,9 @@ export class Sqlite extends Dialect<{ dateTimeMillis?: boolean }> {
         }
         return value;
     }
+    public visitAsOf(asOfNode: AsOfNode): string[] {
+        throw new Error('SQLite does not support AS OF.');
+    }
     public visitReplace(replaceNode: ReplaceNode): string[] {
         // don't use table.column for replaces
         this.visitedReplace = true;

lib/functions.ts

@@ -74,13 +74,22 @@ const jsonbFunctions = [
     'JSONB_AGG'
 ] as const;
 
+// time travel timestamp functions available to cockroachdb
+const timeTravelFunctions = [
+    'STATEMENT_TIMESTAMP',
+    'FOLLOWER_READ_TIMESTAMP',
+    'WITH_MIN_TIMESTAMP',
+    'WITH_MAX_STALENESS'
+] as const;
+
 const standardFunctionNames = [
     ...aggregateFunctions,
     ...scalarFunctions,
     ...hstoreFunctions,
     ...textsearchFunctions,
     ...dateFunctions,
-    ...jsonbFunctions
+    ...jsonbFunctions,
+    ...timeTravelFunctions
 ] as const;
 
 type StandardFunctions = {

lib/node/asOf.ts

@@ -0,0 +1,7 @@
+import { Node } from './node.js';
+
+export class AsOfNode extends Node {
+    constructor() {
+        super('AS OF');
+    }
+}

lib/node/query.ts

@@ -49,6 +49,7 @@ import { TruncateNode } from './truncate.js';
 import { UpdateNode } from './update.js';
 import { ValueExpressionBaseNode } from './_internal.js';
 import { WhereNode } from './where.js';
+import { AsOfNode } from './asOf.js';
 
 // get the first element of an arguments if it is an array, else return arguments as an array
 const getArrayOrArgsAsArray = <T>(args: (T | T[])[]): T[] => {
@@ -152,6 +153,11 @@ export class Query<T> extends ValueExpressionBaseNode {
         return this;
     }
 
+    public asOf(node: INodeable | string): this {
+        this.add(new AsOfNode().add(nodeableOrTextNode(node)));
+        return this;
+    }
+
     public leftJoin(other: INodeable): JoinNode {
         assert(this.type === 'SUBQUERY', 'leftJoin() can only be used on a subQuery');
         return new JoinNode('LEFT', this, other.toNode());

test/dialects/as-of-tests.ts

@@ -0,0 +1,32 @@
+import * as Harness from './support.js';
+import { Sql } from '../../dist/lib.js';
+const post = Harness.definePostTable();
+const user = Harness.defineUserTable();
+const instance = new Sql('postgres');
+
+Harness.test({
+    query: user
+        .select(user.star())
+        .from(user)
+        .asOf(instance.functions.FOLLOWER_READ_TIMESTAMP()),
+    pg: {
+        text: 'SELECT "user".* FROM "user" AS OF SYSTEM TIME FOLLOWER_READ_TIMESTAMP()',
+        string: 'SELECT "user".* FROM "user" AS OF SYSTEM TIME FOLLOWER_READ_TIMESTAMP()'
+    },
+    oracle: {
+        text: 'SELECT "user".* FROM "user" AS OF TIMESTAMP FOLLOWER_READ_TIMESTAMP()',
+        string: 'SELECT "user".* FROM "user" AS OF TIMESTAMP FOLLOWER_READ_TIMESTAMP()'
+    }
+});
+
+Harness.test({
+    query: user.select(user.star()).from([user, post]).asOf('\'-10s\''),
+    pg: {
+        text: 'SELECT "user".* FROM "user" , "post" AS OF SYSTEM TIME \'-10s\'',
+        string: 'SELECT "user".* FROM "user" , "post" AS OF SYSTEM TIME \'-10s\''
+    },
+    oracle: {
+        text: 'SELECT "user".* FROM "user" , "post" AS OF TIMESTAMP \'-10s\'',
+        string: 'SELECT "user".* FROM "user" , "post" AS OF TIMESTAMP \'-10s\''
+    }
+});