docs.sheetjs.com/docz/docs/03-demos/07-data/09-alasql.md

---
title: AlaSQL
pagination_prev: demos/desktop/index
pagination_next: demos/local/index
sidebar_custom_props:
  sql: true
---

import current from '/version.js';

AlaSQL is a pure JavaScript in-memory SQL database.  It has built-in support for
SheetJS through the `XLSX` target operator.

This demo covers basic concepts pertaining to data import and export.  The
official documentation includes advanced examples and deployment tips as well as
strategies for general data processing in AlaSQL expressions.

## NodeJS Usage

:::caution

`alasql` uses an older version of the library.  It can be overridden through a
`package.json` override in the latest versions of NodeJS:

<pre><code parentName="pre" {...{"className": "language-json"}}>{`\
{
  "overrides": {
    "xlsx": "https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz"
  }
}`}
</code></pre>

:::

#### Reading Files

By default, the `XLSX` "from" target automatically adds a `.xlsx` extension.  To
read files with an arbitrary filename, the `autoExt: false` option should be
passed as the second argument:

```sql
SELECT `Name`, `Index` FROM XLSX(
  "pres.numbers" --<< filename is "pres.numbers"
// highlight-start
  , { --<< options are supplied as the second argument to XLSX operator
    autoExt: false --<< do not automatically add ".xlsx" extension!
  }
// highlight-end
) WHERE `Index` < 45
```

By default the workbook is parsed and `sheet_to_json` is used to pull data:

```js
const { promise: alasql } = require("alasql");

(async() => {
  const aoo = await alasql(`SELECT * from XLSX("pres.xlsb", {autoExt: false})`);
  console.log(aoo); // [ { Name: "Bill Clinton", Index: 42 }, ...]
})();
```

#### Writing Files

The `XLSX` "into" target calls `XLSX.writeFile` under the hood:

```js
const { promise: alasql } = require("alasql");

(async() => {
  const data = [
    { Name: "Bill Clinton", Index: 42 },
    { Name: "Someone Else", Index: 47 }
  ];
  await alasql(`SELECT * INTO XLSX("PresMod5.xlsb") FROM ?`, [data]);
  /* PresMod5.xlsb will be created */
})();
```

### NodeJS Example

:::note

This demo was tested on 2023 February 23 against AlaSQL 3.1.0

:::

1) Create an empty folder for the project:

```bash
mkdir alasql
cd alasql
```

2) In the folder, create a stub `package.json` with the `xlsx` override:

```json title="package.json"
{
  "overrides": {
    "xlsx": "https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz"
  }
}
```

3) Install SheetJS and AlaSQL:

```bash
npm i --save alasql@3.1.0 https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz
```

4) Download the test file <https://sheetjs.com/pres.numbers> :

```bash
curl -LO https://sheetjs.com/pres.numbers
```

5) Save the following test script to `SheetJSAlaSQL.js`:

```js title="SheetJSAlaSQL.js"
const { promise: alasql } = require("alasql");

(async() => {
  /* read data from spreadsheet to JS */
  const data = await alasql(`
    SELECT \`Name\`, \`Index\`
      FROM XLSX("pres.numbers", {autoExt:false})
      WHERE \`Index\` < 45
  `);
  console.log(data);

  /* write data from JS to spreadsheet */
  data.push({Name: "Someone Else", Index: 47});
  await alasql(`SELECT * INTO XLSX("SheetJSAlaSQL1.xlsx") FROM ?`, [data]);
})();
```

6) Run the test script

```bash
node SheetJSAlaSQL.js
```

The output should display:

```
[
  { Name: 'Bill Clinton', Index: 42 },
  { Name: 'GeorgeW Bush', Index: 43 },
  { Name: 'Barack Obama', Index: 44 }
]
```

The script should generate `SheetJSAlaSQL1.xlsx` with the additional row:

```csv
Name,Index
Bill Clinton,42
GeorgeW Bush,43
Barack Obama,44
Someone Else,47
```