In Missouri, no person under the age of 21 may legally purchase beer, wine, or liquor. Additionally, it is an offense to even be in possession of alcohol under most circumstances.  It is unlawful for anyone under 21 to purchase beer, wine, or liquor even if accompanied by a parent, legal guardian or spouse who is over the drinking age.  If you are at least 17 years of age but less than 21 years of age, you can be fined up to $1,000 or sentenced to jail for up to one year or both fined and sentenced for purchasing alcohol.

Any place that sells beer, wine, or liquor has a duty to ask for identification for proof of age for all persons who appear to be and might be under age. All places have the right to refuse to sell beer, wine, or liquor to any person who cannot show true proof of age, even if that person is 21 years or older.
 
In addition to the above laws, the city of Columbia also has ordinances relating to alcohol, including Columbia’s open container law.  This ordinance makes it unlawful for any person to possess any alcoholic beverage on any street, sidewalk or city parking facility unless it is in the original container and the seal is unbroken.  The ordinance also makes it unlawful to consume alcohol on any street, sidewalk or city parking facility.