title: What is the difference between MySQL's create index and alter add index?
body: <p>I have a table "data" with column id(varchar), text(varchar), date(date). Creating index on mysql, I use heidiSQL.</p>
  
  <p>When I right click on the column and select create new index (key), the code shows it's using <code>alter table data add index 'index1' ('id,date(10)')</code></p>
  
  <p>What is the difference between this and <code>create index index1 on data ('id,date(10)')</code></p>