Can Golang\'s SQL Package Handle Ad Hoc Queries?

Ad Hoc Queries in Golang's SQL Package

Contrary to the initial impression conveyed by its documentation, the Golang SQL package is capable of facilitating ad hoc and exploratory queries.

The sql.Rows type possesses a Columns method that retrieves the names of the result columns. This information enables the determination of the number of columns, even for unfamiliar queries.

Additionally, the Scan method allows for the retrieval of column values without prior knowledge of their types. It provides options for saving values in their raw form (RawBytes) or as equivalent Go types (interface{}).

Utilizing both the Columns and Scan methods, it is possible to construct a flexible approach to retrieving data from unknown tables or queries. For instance, the following code employs the variadic syntax (...) to dynamically adapt to the number of columns.

columnNames, err := rows.Columns()
if err != nil {
    log.Fatalln(err)
}
columns := make([]interface{}, len(columnNames))
columnPointers := make([]interface{}, len(columnNames))
for i := 0; i < len(columnNames); i++ {
    columnPointers[i] = &columns[i]
}
if err := rows.Scan(columnPointers...); err != nil {
    log.Fatalln(err)
}

This code captures all the decoded column values for the current row in the columns slice. Advance awareness about the table structure or expected column types may facilitate further optimization of the logic.

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