001package gudusoft.gsqlparser.ir.semantic.joinanalysis;
002
003/**
004 * How a {@link JoinEntity} was written in the source SQL.
005 *
006 * <ul>
007 *   <li>{@link #EXPLICIT} — a keyword join ({@code JOIN ... ON},
008 *       {@code LEFT JOIN}, {@code CROSS JOIN}, {@code NATURAL JOIN},
009 *       {@code USING (...)}).</li>
010 *   <li>{@link #COMMA} — a comma-FROM cross product
011 *       ({@code FROM a, b}), modelled as
012 *       {@link SemanticJoinType#IMPLICIT_CROSS}.</li>
013 * </ul>
014 *
015 * <p>Introduced by join-analysis slice 162 (S1).
016 */
017public enum JoinSourceSyntax {
018    EXPLICIT,
019    COMMA
020}