postgresql的分页显示-截取字符串-递归查询

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1.pgsql 分页查询
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select * from table_name limit A offset B
注：A为所需展示的行数
B为查询的起始位置
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select * from table_name where id >B limit A
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2.pgsql 截取字符串函数
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给定子字符串在字符串中的位置 position ('源字符串','子字符串')
截取字符串 substring('源字符串' from 起始位置 for 截取字符串长度);
substring('源字符串',A,B);
注：A:起始位置 B.截取长度
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3.pgsql 递归查询
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从根节点往子节点查询：
with recurse result as(
select id,pid,name from js_city where id=1
union all
select a.id,a.pid,a.name from js_city a join result b on b.id= a.pid)
select id,pid,name from result;