在 PostgreSQL 中解析数值范围

Question

我想生成一个包含一些经过解析的数字范围的字符串。

我有一个 table 和一些数据

b_id,s_id
1,50
1,51
1,53
1,61
1,62
1,63
2,91
2,95
2,96
2,97

在 PostgreSQL 中仅使用 SQL，我如何生成此输出：

b_id,s_seqs
1,"50-51,53,61-63"
2,"91,95-97"

我到底该怎么做？

Answer 1

select b_id, string_agg(seq, ',' order by seq_no) as s_seqs
from (
    select 
        b_id, seq_no,
        replace(regexp_replace(string_agg(s_id::text, ','), ',.+,', '-'), ',', '-') seq
    from (
        select 
            b_id, s_id, 
            sum(mark) over w as seq_no
        from (
            select 
                b_id, s_id, 
                (s_id- 1 <> lag(s_id, 1, s_id) over w)::int as mark
            from my_table
            window w as (partition by b_id order by s_id)
            ) s
        window w as (partition by b_id order by s_id)
        ) s
    group by 1, 2
    ) s
group by 1;

Here you can find从最内层查询向外一步步分析

在 PostgreSQL 中解析数值范围

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