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Articles tagged with #data-science
Problem description & analysis: The field n of a certain database table is used for sorting, and the x field is an integer, sometimes with consecutive 0s. Task: Now we need to add a calculated column def, which requires the initial value of def to b...
Problem description & analysis: SQL Server has two tables, Table1： Table2： Task: Now we need to sort Table1 by ID and traverse each record in sequence: retrieve the record in Table2 that has the same DocNum field as the current record, but with a s...
Problem description & analysis: The MySQL database has two tables: bag table and bag item relationship table. Some bags are supersets of other bags. bag bag_item Task: Now we need to find the superset for each bag: Code comparisons: SQL： SELECT ...
Problem description & analysis: There are four strings separated into two parts by vertical bar, namely: ID|DUE_DATE, 80781|2026–12–01, VARCHAR2|DATE, |yyyy-mm-dd. Task: Now we need to generate a four-field result set, extract the first part of each ...
Problem description & analysis: The second and third fields of a certain database table are the starting year/month, and the ending year/month, respectively, in the format of “year M month”. Task: Now we need to add a calculated column TimePeriods: ...
Problem description & analysis: A certain database table records the execution status of a project, with multiple people participating in the project every day, and one person can participate in multiple tasks of the project in one day. Task: Now we...
