sql_cmd.h

enum enum_sql_command {
SQLCOM_SELECT, SQLCOM_CREATE_TABLE, SQLCOM_CREATE_INDEX, SQLCOM_ALTER_TABLE,
SQLCOM_UPDATE, SQLCOM_INSERT, SQLCOM_INSERT_SELECT,
SQLCOM_DELETE, SQLCOM_TRUNCATE, SQLCOM_DROP_TABLE, SQLCOM_DROP_INDEX,

SQLCOM_SHOW_DATABASES, SQLCOM_SHOW_TABLES, SQLCOM_SHOW_FIELDS,
SQLCOM_SHOW_KEYS, SQLCOM_SHOW_VARIABLES, SQLCOM_SHOW_STATUS,
SQLCOM_SHOW_ENGINE_LOGS, SQLCOM_SHOW_ENGINE_STATUS, SQLCOM_SHOW_ENGINE_MUTEX,
SQLCOM_SHOW_PROCESSLIST, SQLCOM_SHOW_MASTER_STAT, SQLCOM_SHOW_SLAVE_STAT,
SQLCOM_SHOW_GRANTS, SQLCOM_SHOW_CREATE, SQLCOM_SHOW_CHARSETS,
SQLCOM_SHOW_COLLATIONS, SQLCOM_SHOW_CREATE_DB, SQLCOM_SHOW_TABLE_STATUS,
SQLCOM_SHOW_TRIGGERS,

SQLCOM_LOAD,SQLCOM_SET_OPTION,SQLCOM_LOCK_TABLES,SQLCOM_UNLOCK_TABLES,
SQLCOM_GRANT,
SQLCOM_CHANGE_DB, SQLCOM_CREATE_DB, SQLCOM_DROP_DB, SQLCOM_ALTER_DB,
SQLCOM_REPAIR, SQLCOM_REPLACE, SQLCOM_REPLACE_SELECT,
SQLCOM_CREATE_FUNCTION, SQLCOM_DROP_FUNCTION,
SQLCOM_REVOKE,SQLCOM_OPTIMIZE, SQLCOM_CHECK,
SQLCOM_ASSIGN_TO_KEYCACHE, SQLCOM_PRELOAD_KEYS,
SQLCOM_FLUSH, SQLCOM_KILL, SQLCOM_ANALYZE,
SQLCOM_ROLLBACK, SQLCOM_ROLLBACK_TO_SAVEPOINT,
SQLCOM_COMMIT, SQLCOM_SAVEPOINT, SQLCOM_RELEASE_SAVEPOINT,
SQLCOM_SLAVE_START, SQLCOM_SLAVE_STOP,
SQLCOM_BEGIN, SQLCOM_CHANGE_MASTER,
SQLCOM_RENAME_TABLE,
SQLCOM_RESET, SQLCOM_PURGE, SQLCOM_PURGE_BEFORE, SQLCOM_SHOW_BINLOGS,
SQLCOM_SHOW_OPEN_TABLES,
SQLCOM_HA_OPEN, SQLCOM_HA_CLOSE, SQLCOM_HA_READ,
SQLCOM_SHOW_SLAVE_HOSTS, SQLCOM_DELETE_MULTI, SQLCOM_UPDATE_MULTI,
SQLCOM_SHOW_BINLOG_EVENTS, SQLCOM_DO,
SQLCOM_SHOW_WARNS, SQLCOM_EMPTY_QUERY, SQLCOM_SHOW_ERRORS,
SQLCOM_SHOW_STORAGE_ENGINES, SQLCOM_SHOW_PRIVILEGES,
SQLCOM_HELP, SQLCOM_CREATE_USER, SQLCOM_DROP_USER, SQLCOM_RENAME_USER,
SQLCOM_REVOKE_ALL, SQLCOM_CHECKSUM,
SQLCOM_CREATE_PROCEDURE, SQLCOM_CREATE_SPFUNCTION, SQLCOM_CALL,
SQLCOM_DROP_PROCEDURE, SQLCOM_ALTER_PROCEDURE,SQLCOM_ALTER_FUNCTION,
SQLCOM_SHOW_CREATE_PROC, SQLCOM_SHOW_CREATE_FUNC,
SQLCOM_SHOW_STATUS_PROC, SQLCOM_SHOW_STATUS_FUNC,
SQLCOM_PREPARE, SQLCOM_EXECUTE, SQLCOM_DEALLOCATE_PREPARE,
SQLCOM_CREATE_VIEW, SQLCOM_DROP_VIEW,
SQLCOM_CREATE_TRIGGER, SQLCOM_DROP_TRIGGER,
SQLCOM_XA_START, SQLCOM_XA_END, SQLCOM_XA_PREPARE,
SQLCOM_XA_COMMIT, SQLCOM_XA_ROLLBACK, SQLCOM_XA_RECOVER,
SQLCOM_SHOW_PROC_CODE, SQLCOM_SHOW_FUNC_CODE,
SQLCOM_ALTER_TABLESPACE,
SQLCOM_INSTALL_PLUGIN, SQLCOM_UNINSTALL_PLUGIN,
SQLCOM_BINLOG_BASE64_EVENT,
SQLCOM_SHOW_PLUGINS,
SQLCOM_CREATE_SERVER, SQLCOM_DROP_SERVER, SQLCOM_ALTER_SERVER,
SQLCOM_CREATE_EVENT, SQLCOM_ALTER_EVENT, SQLCOM_DROP_EVENT,
SQLCOM_SHOW_CREATE_EVENT, SQLCOM_SHOW_EVENTS,
SQLCOM_SHOW_CREATE_TRIGGER,
SQLCOM_ALTER_DB_UPGRADE,
SQLCOM_SHOW_PROFILE, SQLCOM_SHOW_PROFILES,
SQLCOM_SIGNAL, SQLCOM_RESIGNAL,
SQLCOM_SHOW_RELAYLOG_EVENTS,
SQLCOM_GET_DIAGNOSTICS,
SQLCOM_ALTER_USER,

/*
When a command is added here, be sure it's also added in mysqld.cc
in "struct show_var_st status_vars[]= {" ...
*/
/* This should be the last !!! */
SQLCOM_END
};

命令解析：SQL_parse.cc

eg：

case SQLCOM_SHOW_PROCESSLIST:

　　if(!thd->security_ctx->priv_user[] &&check_global_access(thd,PROCESS_ACL))

   　　 break;

　　mysqld_list_processes(thd,(thd->security_ctx->master_access & PROCESS_ACL ?NullS :thd->security_ctx->priv_user),lex->verbose);

　　break;