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

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AlaSQL	demos/desktop/index	demos/local/index	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:

{`\
{
  "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.xlsb", {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.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:

mkdir alasql
cd alasql

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

{
  "overrides": {
    "xlsx": "https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz"
  }
}

3. Install SheetJS and AlaSQL:

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 :

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

5. 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]);
})();

6. 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