SQLazy: Search for Adjacent Records at a Specified Offset Within Groups
Problem Description In a table, ProductionLine_Number is the grouping field, and within each group records are sorted by date_Time. The task is to search, within each group, all records whose Cardboard_Number equals a specified string, then take the records within a specified offset before and after each matched record, merge and remove duplicates before outputting. Source Data Expected Result In…
To find records with a specific Cardboard_Number within a certain offset of each match in a table organized by ProductionLine_Number and sorted by date_Time, follow these steps. First, sort the data by ProductionLine_Number and then by date_Time within each group. Next, flag the rows that match the target Cardboard_Number value with 1, while leaving the rest as empty.
This step is done separately for each ProductionLine_Number group using the partition clause. Then, use SQLazy's relative-position range syntax flag[-2:2] to select the rows within 2 positions before and after the current row. The max function aggregates these flags to determine if any matched row exists in the window, marking the current row as in_range if true.
After that, filter the results to keep only the rows where in_range equals 1, meaning they fall within the desired offset range of a matched record. Finally, remove any duplicate ids from overlapping offset ranges using distinct, giving the final list of ids that satisfy the conditions. SQLazy simplifies this process, allowing users to express complex logic in a more readable format using business language, rather than writing complex nested SQL queries.
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