08 2021 档案
摘要:partition by:进行分组 ORDER BY:进行排序 row_number:统计行数 select a.* from ( select *, "row_number"() over (partition by hall_id,center_frequency ORDER BY last_d
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摘要:java.lang.Integer java.util.list
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摘要:使用ObjectMapper 字节转对象: object = objectMapper.readValue(byte[], class.class) Object转对象(直接强转报错): object = objectMapper.convertValue(json, class.class)
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摘要:查询表中数据大小: --数据库中单个表的大小(不包含索引) select pg_size_pretty(pg_relation_size('表名')); --查出所有表(包含索引)并排序SELECT table_schema || '.' || table_name AS table_full_na
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