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docs.sheetjs.com/docz/docs/03-demos/07-data/09-alasql.md
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title pagination_prev pagination_next sidebar_custom_props
AlaSQL demos/desktop/index demos/local/index
sql
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<head> </head>

import current from '/version.js'; import CodeBlock from '@theme/CodeBlock';

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.

:::note

This demo was tested in the following environments:

Environment AlaSQL Date
NodeJS 3.1.0 2023-02-23
Standalone (Chrome) 3.0.0 2023-04-09

:::

Live Demo

This demo fetches https://sheetjs.com/pres.numbers, performs a SELECT query using the built-in AlaSQL + SheetJS integration, then displays the result. Using the result as a data source, the demo will write to a new spreadsheet.

Demo AlaSQL Queries (click to show) 
SELECT `Index`,          -- "Index" field is the "Index" column of the sheet
  UPPER(`Name`) AS `Nom` -- "Nom" field will be uppercase of "Name" column
FROM XLSX(?, {           -- Parse the workbook bytes passed to alasql.promise
  autoExt: false         -- This option is required in the browser
})

SELECT *                 -- use every field from every row in dataset
INTO XLSX(               -- export data to file
  "SheetJSAlaSQL.xlsx"   -- filename for export
) FROM ?

:::caution

If the live demo shows a message

alasql undefined

please refresh the page. This is a known bug in the documentation generator.

:::

function SheetJSAlaSQL() {
  const q1 = "SELECT `Index`, UPPER(`Name`) AS `Nom` FROM XLSX(?,{autoExt:false})";
  const q2 = `SELECT * INTO XLSX("SheetJSAlaSQL.xlsx") FROM ?`;
  const url = "https://sheetjs.com/pres.numbers";
  const [rows, setRows] = React.useState([]);
  const loadURL = React.useCallback(async() => {
    if(typeof alasql=="undefined") return setRows([{Nom:"alasql undefined"}]);
    const blob = await (await fetch(url)).blob();
    const data = URL.createObjectURL(blob);
    const res = await alasql.promise(q1,[data]);
    setRows(res);
    await alasql.promise(q2, [res]);
  }, []);
  return ( <>
    <pre><b>URL: </b>{url}<br/><b>Import: </b>{q1}<br/><b>Export: </b>{q2}</pre>
    <table><tr><th>Index</th><th>Nom</th></tr>
      {rows.map(({Nom, Index}) => <tr><td>{Index}</td><td>{Nom}</td></tr>)}
    </table>
    <button onClick={loadURL}>Click to start</button>
  </> );
}

Browser

Standalone Scripts

The Standalone scripts should be loaded before the alasql script:

{`\


`}

Frameworks and Bundlers

alasql uses an older version of the library. It can be overridden through a package.json override. The lines should be added before installing alasql:

{`\
{
  /* add this part before "name" */
  /* highlight-start */
  "overrides": {
    "xlsx": "https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz"
  },
  /* highlight-end */
  "name": "my-project",
  /* ... more fields ... */
`}

After adding the override, AlaSQL can be installed through npm:

npm install --save alasql

In imports, the SheetJS library must be passed to AlaSQL as shown below:

import * as alasql from 'alasql';
import * as XLSX from 'xlsx';
alasql.utils.isBrowserify = false;
alasql.utils.global.XLSX = XLSX;

Reading Files

The XLSX "from" target expects a filename. In the browser, AlaSQL uses object URLs which can be created from Blob or File objects.

The following snippet fetches data and passes to AlaSQL:

const blob = await (await fetch("https://sheetjs.com/pres.numbers")).blob();
const data = URL.createObjectURL(blob);
const res = await alasql.promise("SELECT * FROM XLSX(?, {autoExt: false}", [data]);

By default, the XLSX "from" target automatically adds a .xlsx extension. To read URLs, the autoExt: false option should be passed as the second argument:

SELECT `Name`, `Index` FROM XLSX(
  ? --<< this will be the URL passed into `alasql.promise`
// 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:

(async() => {
  const blob = await (await fetch("https://sheetjs.com/pres.numbers")).blob();
  const data = URL.createObjectURL(blob);
  const aoo = await alasql.promise("SELECT * FROM XLSX(?, {autoExt: false}", [data]);
  console.log(aoo); // [ { Name: "Bill Clinton", Index: 42 }, ...]
})();

Writing Files

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

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

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

NodeJS

:::caution

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

{`\
{
  "overrides": {
    "xlsx": "https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz"
  }
}`}

:::

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:

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:

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

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

Writing Files

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

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

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

NodeJS Example

  1. Create an empty folder for the project:
mkdir alasql
cd alasql
  1. In the folder, create a stub package.json with the xlsx override:

{\ { "overrides": { "xlsx": "https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz" } }}

  1. Install SheetJS and AlaSQL:

{\ npm i --save alasql@3.1.0 https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz}

  1. Download the test file https://sheetjs.com/pres.numbers :
curl -LO https://sheetjs.com/pres.numbers
  1. Save the following test script to 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]);
})();
  1. Run the test script
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:

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