START TRANSACTION
    [transaction_characteristic [, transaction_characteristic] ...]

transaction_characteristic: {
    WITH CONSISTENT SNAPSHOT
  | READ WRITE
  | READ ONLY
}

BEGIN [WORK]
COMMIT [WORK] [AND [NO] CHAIN] [[NO] RELEASE …

[begin_label:] BEGIN
    [statement_list]
END [end_label]

[begin_label:] LOOP
    statement_list
END LOOP [end_label]

[begin_label:] REPEAT
    statement_list
UNTIL search_condition
END REPEAT [end_label]

[begin_label:] WHILE search_condition DO
    statement_list …

SELECT @rownum:=@rownum+1 AS no, t.id, t.name
FROM tree t 
WHERE (@rownum:=0)=0
AND t.`type` = 10
AND t.depth = 2
AND t.parent = 76
ORDER BY t.id
;

SELECT ABS(-10) => 10

SELECT CEIL(1.3) => 2
SELECT CEIL(-1.3) => -1

SELECT FLOOR(1.7) => 1
SELECT FLOOR(-1.7) => -2

SELECT MOD(23, 10 …

SELECT p.email AS email 
FROM Person p
GROUP BY p.email 
HAVING COUNT(*) > 1
;

Input: 
Product table:
+------------+--------------+------------+
| product_id | product_name | unit_price |
+------------+--------------+------------+
| 1          | S8           | 1000       |
| 2          | G4           | 800        |
| 3          | iPhone       | 1400       |
+------------+--------------+------------+
Sales table:
+-----------+------------+----------+------------+----------+-------+
| seller_id | product_id | buyer_id | sale_date  | quantity | price |
+-----------+------------+----------+------------+----------+-------+
| 1         | 1          | 1        | 2019-01-21 | 2        | 2000  |
| 1         | 2          | 2        | 2019-02-17 | 1        | 800   |
| 2         | 2          | 3        | 2019-06 …

SHOW VARIABLES LIKE '%COMMIT%'

autocommit                          ON  <- 여기
binlog_group_commit_sync_delay       0
binlog_group_commit_sync_no_delay_count  0
binlog_order_commits                    ON
innodb_api_bk_commit_interval            5
innodb_commit_concurrency            0
innodb_flush_log_at_trx_commit           1
original_commit_timestamp           36028797018963968

START TRANSACTION …