索引

PostgreSQL/common.sql

@@ -52,3 +52,6 @@ vacuum full study.r;
 -- "(0,2)",3,103
 -- "(0,3)",4,104
 -- 看到空间已经回收
+
+-- 查看数据类型
+select pg_typeof(EXTRACT(EPOCH FROM current_timestamp(0)))

PostgreSQL/index.sql

@@ -0,0 +1,2 @@
+-- 不阻塞的情况下创建索引
+create index concurrently idx_prism_timestamp on activities (timestamp);

PostgreSQL/time.sql

@@ -8,3 +8,6 @@ select msg_time at time zone 'Asia/Shanghai' from msg where id = 1;
 select msg_time at time zone 'UTC+8' from msg where id = 1;
 
 select to_timestamp(1761850339) AT TIME ZONE 'Asia/Shanghai';
+
+-- 将当前时间转换为Unix时间戳
+select EXTRACT(EPOCH FROM current_timestamp(0)) - 60;