错误：“组”处或附近出现语法错误。-这是否意味着此外部数据库与相应版本的PostgreSQL（>=11）不兼容，因此无法识别组语法？如何检查连接到的外部数据库正在运行哪个版本的PostgreSQL？我想知道这是否是问题的根源，或者我确实有一些语法错误并获得

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错误：“组”处或附近出现语法错误。

-这是否意味着此外部数据库与相应版本的PostgreSQL（>=11）不兼容，因此无法识别组语法？如何检查连接到的外部数据库正在运行哪个版本的PostgreSQL？我想知道这是否是问题的根源，或者我确实有一些语法错误并获得它的签名@TarunLalwani。不幸的是，我的Postgres版本是9.5.10。我会相应地更新主题。@jakes:我为Postgres 9.5添加了一个解决方案。请记住在所有问题中披露主要软件版本。关于Postgres 9.5.10的两个注意事项-如果您对此有任何影响：1：始终升级到最新的point版本，在撰写本文时为9.5.24。2、但是考虑升级到当前版本，作为，非常感谢！问这个问题可能太多了（反正我已经接受了你的答案），但是如果你有时间的话——你能看看并解释一下我最初的查询出错的原因吗？我想不出来

CREATE TABLE example_tbl (
  id CHAR(1),
  pid INT,
  sid INT, 
  tid VARCHAR(10),
  other_columns INT
)

INSERT INTO example_tbl (id, pid, sid, tid, other_columns)
VALUES 
('c', 157, 85, 'A32', 1),
 ('c', 157, 85, 'A32', 2),
 ('c', 157, 85, 'A32', 3),
 ('c', 157, 85, 'A32', 4),
 ('c', 157, 85, 'A32', 5),
 ('c', 157, 85, 'A32', 6),
 ('c', 157, 85, 'A32', 7),
 ('c', 157, 85, 'A32', 8),
 ('c', 157, 85, 'A32', 9),
 ('c', 157, 85, 'A32', 10),
 ('c', 157, 85, 'A32', 11),
 ('Q', 157, 81, 'A62', 1),
 ('Q', 157, 81, 'A62', 2),
 ('Q', 157, 81, 'A62', 3),
 ('Q', 157, 81, 'A62', 4),
 ('Q', 157, 81, 'A62', 5),
 ('Q', 157, 81, 'A62', 6),
 ('Q', 157, 81, 'A62', 7),
 ('Q', 157, 81, 'A62', 8),
 ('Q', 157, 81, 'A62', 9),
 ('Q', 157, 81, 'A62', 10),
 ('Q', 157, 81, 'A62', 11),
 ('f', 598, 51, 'A62', NULL),
 ('w', 598, 49, 'A32', 9),
 ('Z', 598, 44, 'A62', NULL),
 ('r', 598, 16, 'A32', 10),
 ('O', 118, 93, 'A32', 1),
 ('G', 118, 38, 'A32', 4),
 ('U', 118, 90, 'A32', 1),
 ('U', 118, 90, 'A32', 2),
 ('U', 118, 90, 'A32', 3),
 ('U', 118, 90, 'A32', 4),
 ('U', 118, 90, 'A32', 5),
 ('U', 118, 90, 'A32', 6),
 ('U', 118, 90, 'A32', 7),
 ('U', 118, 90, 'A32', 8),
 ('U', 118, 90, 'A32', 9),
 ('U', 118, 90, 'A32', 10),
 ('U', 118, 90, 'A32', 11),
 ('m', 118, 37, 'A62', 1),
 ('J', 118, 54, 'A32', 20),
 ('a', 118, 59, 'A32', 11),
 ('s', 118, 18, 'A62', 8),
 ('y', 118, 33, 'A62', NULL),
 ('N', 118, 79, 'A62', NULL),
 ('l', 118, 35, 'A32', 9),
 ('n', 118, 63, 'A32', 5),
 ('R', 118, 86, 'A62', 1),
 ('R', 118, 86, 'A62', 2),
 ('R', 118, 86, 'A62', 3),
 ('R', 118, 86, 'A62', 4),
 ('R', 118, 86, 'A62', 5),
 ('R', 118, 86, 'A62', 6),
 ('R', 118, 86, 'A62', 7),
 ('R', 118, 86, 'A62', 8),
 ('R', 118, 86, 'A62', 9),
 ('R', 118, 86, 'A62', 10),
 ('R', 118, 86, 'A62', 11),
 ('H', 118, 23, 'A32', 1),
 ('H', 118, 23, 'A32', 2),
 ('H', 118, 23, 'A32', 3),
 ('H', 118, 23, 'A32', 4),
 ('H', 118, 23, 'A32', 5),
 ('H', 118, 23, 'A32', 6),
 ('H', 118, 23, 'A32', 7),
 ('H', 118, 23, 'A32', 8),
 ('H', 118, 23, 'A32', 9),
 ('H', 118, 23, 'A32', 10),
 ('H', 118, 23, 'A32', 11),
 ('B', 118, 43, 'A62', 39),
 ('h', 118, 60, 'A62', NULL),
 ('p', 118, 72, 'A32', 1),
 ('v', 118, 22, 'A32', 5),
 ('I', 118, 89, 'A62', 9),
 ('T', 118, 17, 'A62', 1),
 ('F', 118, 41, 'A32', 10),
 ('z', 118, 55, 'A32', 6),
 ('Y', 118, 75, 'A32', NULL),
 ('u', 118, 48, 'A62', 9),
 ('x', 783, 27, 'A32', 10),
 ('V', 783, 11, 'A62', 8),
 ('i', 783, 61, 'A62', 1),
 ('i', 783, 61, 'A62', 2),
 ('i', 783, 61, 'A62', 3),
 ('i', 783, 61, 'A62', 4),
 ('i', 783, 61, 'A62', 5),
 ('i', 783, 61, 'A62', 6),
 ('i', 783, 61, 'A62', 7),
 ('i', 783, 61, 'A62', 8),
 ('i', 783, 61, 'A62', 9),
 ('i', 783, 61, 'A62', 10),
 ('i', 783, 61, 'A62', 11);

WITH example_tbl_with_offset AS (
    SELECT * FROM example_tbl
    LEFT JOIN (SELECT id, COUNT(id)::int AS lag_offset
               FROM example_tbl
               GROUP BY id) AS offset_tbl
    USING (id)
)
SELECT
    *, 
    LAG(id, lag_offset) OVER (PARTITION BY tid
                              ORDER BY (CASE 
                                WHEN pid = 157 THEN 1
                                WHEN pid = 598 THEN 2
                                WHEN pid = 118 THEN 3
                                WHEN pid = 783 THEN 4
                              END, sid
    )) AS prev_id 
FROM example_tbl_with_offset;

CREATE TABLE expected_output (
  id CHAR(1),
  pid INT,
  sid INT, 
  tid VARCHAR(10),
  prev_id CHAR(1)
)

INSERT INTO expected_output (id, pid, sid, tid, prev_id)
VALUES 
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('Q', 157, 81, 'A62', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('c', 157, 85, 'A32', NULL),
 ('r', 598, 16, 'A32', 'c'),
 ('Z', 598, 44, 'A62', 'Q'),
 ('w', 598, 49, 'A32', 'r'),
 ('f', 598, 51, 'A62', 'Z'),
 ('T', 118, 17, 'A62', 'f'),
 ('s', 118, 18, 'A62', 'T'),
 ('v', 118, 22, 'A32', 'w'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('H', 118, 23, 'A32', 'v'),
 ('y', 118, 33, 'A62', 's'),
 ('l', 118, 35, 'A32', 'H'),
 ('m', 118, 37, 'A62', 'y'),
 ('G', 118, 38, 'A32', 'I'),
 ('F', 118, 41, 'A32', 'G'),
 ('B', 118, 43, 'A62', 'm'),
 ('u', 118, 48, 'A62', 'B'),
 ('J', 118, 54, 'A32', 'F'),
 ('z', 118, 55, 'A32', 'J'),
 ('a', 118, 59, 'A32', 'z'),
 ('h', 118, 60, 'A62', 'u'),
 ('n', 118, 63, 'A32', 'a'),
 ('p', 118, 72, 'A32', 'n'),
 ('Y', 118, 75, 'A32', 'p'),
 ('N', 118, 79, 'A62', 'h'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('R', 118, 86, 'A62', 'N'),
 ('I', 118, 89, 'A62', 'R'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('U', 118, 90, 'A32', 'Y'),
 ('O', 118, 93, 'A32', 'U'),
 ('V', 783, 11, 'A62', 'I'),
 ('x', 783, 27, 'A32', 'O'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V'),
 ('i', 783, 61, 'A62', 'V');
 

SELECT * FROM expected_output
ORDER BY tid, CASE 
            WHEN pid = 157 THEN 1
            WHEN pid = 598 THEN 2
            WHEN pid = 118 THEN 3
            WHEN pid = 783 THEN 4
          END, sid;

select m.* from (
select *, lag(id,1) over ( PARTITION BY tid
order by (CASE 
                                WHEN pid = 157 THEN 1
                                WHEN pid = 598 THEN 2
                                WHEN pid = 118 THEN 3
                                WHEN pid = 783 THEN 4
                              END, sid
    )
) from ( select distinct * from example_tbl et )a )
m,
example_tbl n
where m.id = n.id and m.pid = n.pid and m.sid = n.sid and m.tid = n.tid
order by (CASE 
                                WHEN m.pid = 157 THEN 1
                                WHEN m.pid = 598 THEN 2
                                WHEN m.pid = 118 THEN 3
                                WHEN m.pid = 783 THEN 4
                              END, m.sid
    )