sort by Timestamp: The prev() function requires the data to be in a specific, ordered sequence to access the "previous" row. The sort operator is used first to arrange all rows chronologically by the Timestamp column.

extend ...: After sorting, the extend operator adds new columns to the table. In this case, it adds PrevMeterReading and PrevTimestamp, calculating their values by using the prev() function to pull data from the preceding row.

project ...: Finally, the project operator selects and orders the columns (city, Area, MeterReading, etc.) to match the exact format specified in the desired output table.

Microsoft (Azure Data Explorer Documentation) - sort operator:

Quote/Section: "Sorts the rows of the input table into order by one or more columns."

Source: Microsoft Docs, "sort operator", https(://)learn.microsoft.com/en-us/azure/data-explorer/kusto/query/sort-operator

Microsoft (Azure Data Explorer Documentation) - prev() function:

Quote/Section: "Returns the value of a column in a previous row within a serialized row set... The row set is serialized by the sort operator."

Source: Microsoft Docs, "prev()", https(://)learn.microsoft.com/en-us/azure/data-explorer/kusto/query/prev-function

Microsoft (Azure Data Explorer Documentation) - extend operator:

Quote/Section: "Create calculated columns and append them to the result set."

Source: Microsoft Docs, "extend operator", https(://)learn.microsoft.com/en-us/azure/data-explorer/kusto/query/extend-operator

Microsoft (Azure Data Explorer Documentation) - project operator:

Quote/Section: "Select the columns to include, rename or drop, and insert new computed columns."

Source: Microsoft Docs, "project operator", https(://)learn.microsoft.com/en-us/azure/data-explorer/kusto/query/project-operator