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* 批量like
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```sql
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like any (array['%.jpg','%.jpeg'])
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```
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* 创建序列
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```sql
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create SEQUENCE id_seq
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START WITH 1
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INCREMENT BY 1
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NO MINVALUE
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NO MAXVALUE
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CACHE 1;
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alter table kx_hospital ALTER COLUMN id set DEFAULT nextval('_id_seq')
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```
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* 获取当前时间绝对秒
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```sql
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select floor(extract(epoch from now()))
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```
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* 雪花ID函数
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```sql
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create SEQUENCE table_id_seq
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START WITH 1
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INCREMENT BY 1
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NO MINVALUE
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NO MAXVALUE
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CACHE 1;
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CREATE OR REPLACE FUNCTION "public"."snow_next_id"(OUT "result" int8)
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RETURNS "pg_catalog"."int8" AS $BODY$
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DECLARE
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our_epoch bigint := 1314220021721;
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seq_id bigint;
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now_millis bigint;
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shard_id int := 5;
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BEGIN
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seq_id := nextval('table_id_seq') % 1024;
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SELECT FLOOR(EXTRACT(EPOCH FROM clock_timestamp()) * 1000) INTO now_millis;
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result := (now_millis - our_epoch) << 23;
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result := result | (shard_id << 10);
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result := result | (seq_id);
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END;
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$BODY$
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LANGUAGE plpgsql VOLATILE
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COST 100
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```
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* count统计过滤及去重
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```sql
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count(distinct(speaker_id||speak_time||content)) FILTER (where t.mark='text') ----- 使用distinct 去重 filter用于过滤
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```
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* PG 操作schema
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```sql
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drop SCHEMA "public" CASCADE --强制删除，包含模式下所有对象（表、函数等）
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create SCHEMA "public" --创建
|
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alter schema name RENAME TO new_name -- 修改模式名称
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alter schema name OWNER TO new_owner -- 修改拥有者
|
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|
```
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|
* 获取单位时间间隔时间
|
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|
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|
|
```sql
|
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|
|
-- 获取6个月前时间
|
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|
|
select to_char((select now() - interval '6 month'),'yyyy-MM-dd hh24:mi:ss')
|
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|
|
|
```
|
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* 窗口函数分组统计(根据collect_code分组，并以collect_time 倒序)
|
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|
|
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|
|
```sql
|
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|
|
select collect_value,row_number() over(PARTITION by collect_code ORDER BY collect_time desc) from nc_data_collect_value_test
|
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|
|
|
```
|
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|
|
* lead函数获取上一条记录，并计算增量
|
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|
|
|
|
|
|
|
|
|
|
```sql
|
|
|
|
|
|
select create_date,node_value as total,next_day_total,next_day_total::int8-node_value::int8 as increment from (
|
|
|
|
|
|
with a as (SELECT create_date, node_value FROM nc_data_node_value_detail WHERE node_code = '' ORDER BY create_date DESC )
|
|
|
|
|
|
select create_date,node_value,lead(node_value,1) over (ORDER BY create_date) next_day_total FROM a ORDER BY create_date desc) tt
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
* lag函数获取下一条记录
|
|
|
|
|
|
|
|
|
|
|
|
```sql
|
|
|
|
|
|
select create_date,node_value as total,next_day_total,abs(next_day_total::int8-node_value::int8) as increment from (
|
|
|
|
|
|
with a as (SELECT create_date, node_value FROM nc_data_node_value_detail WHERE node_code = '' ORDER BY create_date DESC )
|
|
|
|
|
|
select create_date,node_value,lag(node_value,1) over (ORDER BY create_date) next_day_total FROM a ORDER BY create_date desc) tt
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
+ 序列生成
|
|
|
|
|
|
```sql
|
|
|
|
|
|
# 时间序列
|
|
|
|
|
|
# 例：生成从2021年到2023年
|
|
|
|
|
|
select to_char(generate_series(to_date('2021','yyyy'),to_date('2023','yyyy'),'1 years'),'yyyy')
|
|
|
|
|
|
# 生成今天24小时
|
|
|
|
|
|
select to_char(generate_series(to_timestamp(current_date || ' 00:00:00', 'yyyy-MM-dd HH24:mi:ss'),
|
|
|
|
|
|
to_timestamp(current_date || ' 23:59:59', 'yyyy-MM-dd HH24:mi:ss'), '1 hour'),'yyyy-MM-dd HH24:mi:ss')
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
+ 获取本月第1天和最后一天
|
|
|
|
|
|
```sql
|
|
|
|
|
|
select date_trunc('month',current_date),date_trunc('month',current_date)+interval '1 month - 1 day';
|
|
|
|
|
|
```
|
