Sample Decimal Field:

Sample Code:

Apex Class:

public with sharing class OpportunityController {
    
    @AuraEnabled( cacheable = true )
    public static List < Opportunity > fetchOpptys(){
        
        return [
            SELECT Id, Name, AccountId, Account.Name, Decimal__c
            FROM Opportunity LIMIT 10
        ];
        

    }
}

Lightning Web Component:

HTML:

<template>  
    <lightning-card title="Opportunities" icon-name="custom:custom63">  
        <div class="slds-m-around_medium">  
            <template if:true={availableOpportunities}>      
                <lightning-datatable
                    key-field="Id"
                    data={availableOpportunities}
                    columns={columns}
                    hide-checkbox-column="true"
                    show-row-number-column="true">
                </lightning-datatable>  
            </template>      
            <template if:true={error}>  
                {error}>                  
            </template>  
        </div>  
    </lightning-card>
</template>

JavaScript:

import { LightningElement, wire } from 'lwc';
import fetchOpptys from '@salesforce/apex/OpportunityController.fetchOpptys';
 
const columns = [
    { label: 'Name', fieldName: 'Name' },
    { label: 'Decimal', fieldName: 'Decimal__c', type: 'number',
    typeAttributes: { maximumFractionDigits: '2' } },
    { label: 'Account Name', fieldName: 'AccountURL', type: 'url',
    typeAttributes: { label: { fieldName: 'AccountName' }, target: '_blank'} }
];

export default class DataTable extends LightningElement {
     
    availableOpportunities;
    error;
    columns = columns;

    @wire( fetchOpptys )  
    wiredAccount( { error, data } ) {

        if ( data ) {

            let tempRecs = [];
            console.log( 'Fetched Data - ' + JSON.stringify( data ) );
            data.forEach( ( record ) => {

                let tempRec = Object.assign( {}, record );  

                if ( tempRec.AccountId ) {

                    tempRec.AccountName = tempRec.Account.Name;
                    tempRec.AccountURL = '/' + tempRec.AccountId;

                }
                
                tempRecs.push( tempRec );
                
            });
            this.availableOpportunities = tempRecs;
            this.error = undefined;

        } else if ( error ) {

            this.error = error;
            this.availableOpportunities = undefined;

        }

    }

}

JS-meta.xml:

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>52.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightning__Tab</target>
    </targets>
</LightningComponentBundle>

Output: