如何使用Postgres中的窗口功能选择特定的更改

在PostgreSQL 8.4中，您可以使用窗口函数LAG访问上一行并进行比较，以查看其是否具有“ from”和“ to”相同的值：

SELECt "from", "to", timestampFROM(    SELECt        "from",        "to",        timestamp,        LAG(("from", "to")) OVER (ORDER BY timestamp) AS prev    FROM Table1) T1WHERe ("from", "to") IS DISTINCT FROM prev

结果：

from  to    timestamp1     2     0000        1     3     0003        1     2     0005