MySQL Database Schema for Volleyball
Like Gaius said, review the answers at How-to implement an entity with an unknown maximum number of attributes?

Rewriting for MySQL Syntax from the answer by Eric Humphrey at above link:

You could do this. It would allow good performance for normal duration games, while allowing you to also store long running games.

CREATE TABLE InningRuns (
    GameId INT NOT NULL AUTO_INCREMENT,
    Team CHAR(4) NOT NULL, --'Home','Away'
    Inning1 TINYINT, --Seeing how more than 255 runs are not really possible in an inning
    Inning2 TINYINT,
    [...],
    Inning9 TINYINT,
    ExtraInnings VARCHAR(2000), --Use to hold any runs in extra innings, store multiple values using some delimiter like comma (,), pipe (|), semicolon (;), or anything that is not part of the data.
    PRIMARY KEY (GameId, Team)
)


You could further normalize and have a row for each unique combination of game, team, &amp; inning. This would allow you as many innings as the InningId datatype would allow.

CREATE TABLE InningRuns (
    InningRunId INT NOT NULL AUTO_INCREMENT,
    GameId INT NOT NULL,
    Team CHAR(4) NOT NULL, --'Home','Away'
    InningId TINYINT, --Seeing how more than 255 innings might be excessive
    Runs TINYINT,
    PRIMARY KEY (InningRunId),
    UNIQUE (GameId, Team, InningId)
)