GTS 的隔离级别默认为读未提交,该模式下本文表中的 select 语句的 SQL 修饰用法都是支持的;使用 hint 可以让 GTS 达到读已提交,该模式下 select 语句的用法只能部分支持。

GTS 的读 hint 为:/+txc({ 'LEVEL':'READCOMMITED'})/,用法举例如 /+txc({ ‘LEVEL’:’READCOMMITED’})/select name from tb where id =1

DML语句支持

类型 SQL 实例 是否支持
AND & OR
UPDATE …
WHERE col_name1=expr1 AND col_name2= expr2
LIKE
UPDATE ...
WHERE col_name1 LIKE 'NE'
通配符
UPDATE ...
WHERE col_name1 LIKE 'NE%'
BETWEEN
UPDATE ...
WHERE col_name1 BETWEEN expr1 AND expr2
ON DUPLICATE
INSERT INTO tb1_name [(col_name,...)]VALUES ({expr | DEFAULT},...),(...),...[ ON DUPLICATE KEY UPDATE col_name=expr, ... ]

Select 语句支持

类型 SQL 实例 读未提交 读已提交
AND & OR
SELECT *
FROM tb1_name
WHERE col_name1=expr1 AND col_name2= expr2
ORDER BY
SELECT col_name1, col_name2
FROM tb1_name
ORDER BY col_name1
GROUP BY
SELECT col_name1, col_name2
FROM tb1_name
GROUP BY col_name1
LIKE
SELECT col_name1, col_name2
FROM tb1_name
WHERE col_name1 LIKE 'NE'
通配符
SELECT col_name1, col_name2
FROM tb1_name
WHERE col_name1 LIKE 'NE%'
EXISTS
SELECT col_name1, col_name2
FROM tb1_name
WHERE EXISTS (expr1)
IN
SELECT col_name1, col_name2
FROM tb1_name
WHERE col_name1 IN (expr1, expr2,...)
BETWEEN
SELECT col_name1, col_name2
FROM tb1_name
WHERE col_name1 BETWEEN expr1 AND expr2
ON DUPLICATE
INSERT INTO tb1_name [(col_name,...)]VALUES ({expr | DEFAULT},...),(...),...[ ON DUPLICATE KEY UPDATE col_name=expr, ... ]
ALIASES
SELECT t1. col_name1, t2.col_name2
FROM tb1_name AS t1, tb2_name AS t2
WHERE t1. col_name=expr
AND t2. col_name=expr
TOP
SELECT TOP 2 *
FROM tb1_name
LIMIT
SELECT col_name1, col_name2
FROM tb1_name
LIMIT 5
  • JOIN
  • INNER JOIN
  • LEFT JOIN
  • RIGHT JOIN
  • FULL JOIN
SELECT col_name1, col_name2
FROM tb1_name
JOIN tb2_name>ON tb1_name. col_name1= tb2_name. col_name1
  • UNION
  • UNION ALL
  • SELECT INTO
SELECT col_name1, col_name2
FROM tb1_name
UNION
SELECT col_name1, col_name2
FROM tb2_name