The lag function does calculations on this column. Exploring the PostgreSQL Window lag function There’s a further exploration part of one of the Launch School SQL exercises that asks you to make use of the Window lag function to do some. Scalarexpression: We define a column name or expression in this argument. In other words, from the current row the LAG () function can access data of the previous row, or the row before the previous row, and so on. 1 2 LAG (scalarexpression ,offset ,default) OVER ( partitionbyclause orderbyclause ) It uses following arguments. If you need to set these up use the following links to setup: streaming replication and replication slots. PostgreSQL LAG () function provides access to a row that comes before the current row at a specified physical offset. ntile(numbuckets integer), bigint, An integer ranging from 1 to the argument value, dividing the partition as equally as possible. This tutorial assumes you have already setup 1) streaming replication between a primary and a replica PostgreSQL database cluster, and 2) are using replication slots. ![]() ![]() Learn how to monitor native PostgreSQL replication using the system views and functions PostgreSQL provides. In the above query, we use the LAG window function to calculate previous month sales, and use it to calculate month over month growth in PostgreSQL.
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