DQL vs DDL vs DCL vs DML

SQL consists of many types of statements, they may be informally classed as sublanguages:

• Data Manipulation Language (DML)
  • DML is about content, data, "rows"
  • e.g. INSERT, UPDATE or DELETE.
• Data definition or data description language (DDL)
  • DDL is about table, index, schema, metadata, "columns"
  • e.g. CREATE, ALTER, TRUNCATE or DROP.
• data control language (DCL)
  • DCL is about authorization, it controls access to data stored in a database.
  • e.g. GRANT, REVOKE
• Data query language (DQL)
  • DQL is used for performing queries on the data within schema objects.
  • e.g. SELECT, FROM, WHERE