npm package: @rechat/squel
Description: SQL query string builder
Author: Ramesh Nair
Latest version: 5.15.1

# squel - SQL query string builder

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A flexible and powerful SQL query string builder for Javascript.

Full documentation (guide and API) at [https://hiddentao.com/squel/](https://hiddentao.com/squel/).

## Features

* Works in node.js and in the browser.
* Supports the standard SQL queries: SELECT, UPDATE, INSERT and DELETE.
* Supports non-standard commands for popular DB engines such as MySQL.
* Supports paramterized queries for safe value escaping.
* Can be customized to build any query or command of your choosing.
* Uses method chaining for ease of use.
* Small: ~7 KB minified and gzipped
* And much more, [see the guide..](https://hiddentao.com/squel/)

**WARNING: Do not ever pass queries generated on the client side to your web server for execution.** Such a configuration would make it trivial for a casual attacker to execute arbitrary queries&mdash;as with an SQL-injection vector, but much easier to exploit and practically impossible to protect against.

_Note: Squel is suitable for production use, but you may wish to consider more
actively developed alternatives such as [Knex](http://knexjs.org/)_

## Installation

Install using [npm](http://npmjs.org/):

```bash
$ npm install squel
```

## Available files

* `squel.js` - unminified version of Squel with the standard commands and all available non-standard commands added
* `squel.min.js` - minified version of `squel.js`
* `squel-basic.js` - unminified version of Squel with only the standard SQL commands
* `squel-basic.min.js` - minified version of `squel-basic.js`


## Examples

Before running the examples ensure you have `squel` installed and enabled at the top of your script:

    var squel = require("squel");

### SELECT

```javascript
// SELECT * FROM table
squel.select()
    .from("table")
    .toString()

// SELECT t1.id, t2.name FROM table `t1` LEFT JOIN table2 `t2` ON (t1.id = t2.id) WHERE (t2.name <> 'Mark') AND (t2.name <> 'John') GROUP BY t1.id
squel.select()
    .from("table", "t1")
    .field("t1.id")
    .field("t2.name")
    .left_join("table2", "t2", "t1.id = t2.id")
    .group("t1.id")
    .where("t2.name <> 'Mark'")
    .where("t2.name <> 'John'")
    .toString()

// SELECT `t1`.`id`, `t1`.`name` as "My name", `t1`.`started` as "Date" FROM table `t1` WHERE age IN (RANGE(1, 1.2)) ORDER BY id ASC LIMIT 20
squel.select({ autoQuoteFieldNames: true })
    .from("table", "t1")
    .field("t1.id")
    .field("t1.name", "My name")
    .field("t1.started", "Date")
    .where("age IN ?", squel.str('RANGE(?, ?)', 1, 1.2))
    .order("id")
    .limit(20)
    .toString()
```

You can build parameterized queries:

```js
/*
{
    text: "SELECT `t1`.`id`, `t1`.`name` as "My name", `t1`.`started` as "Date" FROM table `t1` WHERE age IN (RANGE(?, ?)) ORDER BY id ASC LIMIT 20",
    values: [1, 1.2]
}
*/
squel.select({ autoQuoteFieldNames: true })
    .from("table", "t1")
    .field("t1.id")
    .field("t1.name", "My name")
    .field("t1.started", "Date")
    .where("age IN ?", squel.str('RANGE(?, ?)', 1, 1.2))
    .order("id")
    .limit(20)
    .toParam()
```


You can use nested queries:

```javascript
// SELECT s.id FROM (SELECT * FROM students) `s` INNER JOIN (SELECT id FROM marks) `m` ON (m.id = s.id)
squel.select()
    .from( squel.select().from('students'), 's' )
    .field('id')
    .join( squel.select().from('marks').field('id'), 'm', 'm.id = s.id' )
    .toString()
```

### UPDATE

```javascript
// UPDATE test SET f1 = 1
squel.update()
    .table("test")
    .set("f1", 1)
    .toString()

// UPDATE test, test2, test3 AS `a` SET test.id = 1, test2.val = 1.2, a.name = "Ram", a.email = NULL, a.count = a.count + 1
squel.update()
    .table("test")
    .set("test.id", 1)
    .table("test2")
    .set("test2.val", 1.2)
    .table("test3","a")
    .setFields({
        "a.name": "Ram",
        "a.email": null,
        "a.count = a.count + 1": undefined
    })
    .toString()
```

### INSERT

```javascript
// INSERT INTO test (f1) VALUES (1)
squel.insert()
    .into("test")
    .set("f1", 1)
    .toString()

// INSERT INTO test (name, age) VALUES ('Thomas', 29), ('Jane', 31)
squel.insert()
    .into("test")
    .setFieldsRows([
        { name: "Thomas", age: 29 },
        { name: "Jane", age: 31 }    
    ])
    .toString()
```

### DELETE

```javascript
// DELETE FROM test
squel.delete()
    .from("test")
    .toString()

// DELETE FROM table1 WHERE (table1.id = 2) ORDER BY id DESC LIMIT 2
squel.delete()
    .from("table1")
    .where("table1.id = ?", 2)
    .order("id", false)
    .limit(2)
```

### Paramterized queries

Use the `useParam()` method to obtain a parameterized query with a separate list of formatted parameter values:

```javascript
// { text: "INSERT INTO test (f1, f2, f3, f4, f5) VALUES (?, ?, ?, ?, ?)", values: [1, 1.2, "TRUE", "blah", "NULL"] }
squel.insert()
    .into("test")
    .set("f1", 1)
    .set("f2", 1.2)
    .set("f3", true)
    .set("f4", "blah")
    .set("f5", null)
    .toParam()
```


### Expression builder

There is also an expression builder which allows you to build complex expressions for `WHERE` and `ON` clauses:

```javascript
// test = 3 OR test = 4
squel.expr()
    .or("test = 3")
    .or("test = 4")
    .toString()

// test = 3 AND (inner = 1 OR inner = 2) OR (inner = 3 AND inner = 4 OR (inner IN ('str1, 'str2', NULL)))
squel.expr()
    .and("test = 3")
    .and(
        squel.expr()
            .or("inner = 1")
            .or("inner = 2")
    )
    .or(
        squel.expr()
            .and("inner = ?", 3)
            .and("inner = ?", 4)
            .or(
                squel.expr()
                    .and("inner IN ?", ['str1', 'str2', null])
            )
    )
    .toString()

// SELECT * FROM test INNER JOIN test2 ON (test.id = test2.id) WHERE (test = 3 OR test = 4)
squel.select()
    .join( "test2", null, squel.expr().and("test.id = test2.id") )
    .where( squel.expr().or("test = 3").or("test = 4") )
```

### Custom value types

By default Squel does not support the use of object instances as field values. Instead it lets you tell it how you want
specific object types to be handled:

```javascript
// handler for objects of type Date
squel.registerValueHandler(Date, function(date) {
  return date.getFullYear() + '/' + (date.getMonth() + 1) + '/' + date.getDate();
});

squel.update().
  .table('students')
  .set('start_date', new Date(2013, 5, 1))
  .toString()

// UPDATE students SET start_date = '2013/6/1'
```


_Note that custom value handlers can be overridden on a per-instance basis (see the [docs](https://hiddentao.com/squel/))_

### Custom queries

Squel allows you to override the built-in query builders with your own as well as create your own types of queries:

```javascript
// ------------------------------------------------------
// Setup the PRAGMA query builder
// ------------------------------------------------------
var util = require('util');   // to use util.inherits() from node.js

var CommandBlock = function() {};
util.inherits(CommandBlock, squel.cls.Block);

// private method - will not get exposed within the query builder
CommandBlock.prototype._command = function(_command) {
  this._command = _command;
}

// public method - will get exposed within the query builder
CommandBlock.prototype.compress = function() {
  this._command('compress');
};

CommandBlock.prototype.buildStr = function() {
  return this._command.toUpperCase();
};


// generic parameter block
var ParamBlock = function() {};
util.inherits(ParamBlock, squel.cls.Block);

ParamBlock.prototype.param = function(p) {
  this._p = p;
};

ParamBlock.prototype.buildStr = function() {
  return this._p;
};


// pragma query builder
var PragmaQuery = function(options) {
  squel.cls.QueryBuilder.call(this, options, [
      new squel.cls.StringBlock(options, 'PRAGMA'),
      new CommandBlock(),
      new ParamBlock()
  ]);
};
util.inherits(PragmaQuery, squel.cls.QueryBuilder);


// convenience method (we can override built-in squel methods this way too)
squel.pragma = function(options) {
  return new PragmaQuery(options)
};


// ------------------------------------------------------
// Build a PRAGMA query
// ------------------------------------------------------

squel.pragma()
  .compress()
  .param('test')
  .toString();

// 'PRAGMA COMPRESS test'
```

Examples of custom queries in the wild:

 * https://github.com/bostrt/squel-top-start-at (blog post about it: http://blog.bostrt.net/extending-squel-js/)


## Non-standard SQL

Squel supports the standard SQL commands and reserved words. However a number of database engines provide their own
non-standard commands. To make things easy Squel allows for different 'flavours' of SQL to be loaded and used.

At the moment Squel provides `mysql`, `mssql` and `postgres` flavours which augment query builders with additional commands (e.g. `INSERT ... RETURNING`
for use with Postgres).

To use this in node.js:

```javascript
var squel = require('squel').useFlavour('postgres');
```

For the browser:

```html
<script type="text/javascript" src="https://rawgithub.com/hiddentao/squel/master/squel.min.js"></script>
<script type="text/javascript">
  squel = squel.useFlavour('postgres');
</script>
```

(Internally the flavour setup method simply utilizes the [custom query mechanism](http://hiddentao.github.io/squel/#custom_queries) to effect changes).

Read the the [API docs](http://hiddentao.github.io/squel/api.html) to find out available commands. Flavours of SQL which get added to
Squel in the future will be usable in the above manner.

## Building it

To build the code and run the tests:

    $ npm install
    $ npm test <-- this will build the code and run the tests

## Releasing it

Instructions for creating a new release of squel are in `RELEASE.md`.


## Contributing

Contributions are welcome! Please see `CONTRIBUTING.md`.

## Older verions

**Note: The latest Squel version only works on Node 0.12 or above. Please use Squel 4.4.1 for Node <0.12. The [old 4.x docs](http://hiddentao.github.io/squel/v4/index.html) are also still available.**


## Ports to other languages

* .NET - https://github.com/seymourpoler/Squel.net
* Crystal - https://github.com/seymourpoler/Squel.crystal

## License

MIT - see LICENSE.md