A library designed to let you easily turn any arbitrary sql.Rows result from a query into a CSV file with a minimum of fuss. Remember to handle your errors and close your rows (not demonstrated in every example).
Importing the package
import (
"database/sql"
_ "github.com/go-sql-driver/mysql" // or the driver of your choice
"github.com/joho/sqltocsv"
)Dumping a query to a file
// we're assuming you've setup your sql.DB etc elsewhere
rows, _ := db.Query("SELECT * FROM users WHERE something=72")
err := sqltocsv.WriteFile("~/important_user_report.csv", rows)
if err != nil {
panic(err)
}Return a query as a CSV download on the world wide web
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
rows, err := db.Query("SELECT * FROM users WHERE something=72")
if err != nil {
http.Error(w, err, http.StatusInternalServerError)
return
}
defer rows.Close()
w.Header().Set("Content-type", "text/csv")
w.Header().Set("Content-Disposition", "attachment; filename=\"report.csv\"")
sqltocsv.Write(w, rows)
})
http.ListenAndServe(":8080", nil)Write and WriteFile should do cover the common cases by the power of Sensible Defaults™ but if you need more flexibility you can get an instance of a Converter and fiddle with a few settings.
rows, _ := db.Query("SELECT * FROM users WHERE something=72")
csvConverter := sqltocsv.New(rows)
csvConverter.TimeFormat = time.RFC822
csvConverter.Headers = append(rows.Columns(), "extra_column_one", "extra_column_two")
csvConverter.SetRowPreProcessor(func (columns []string) (bool, []string) {
// exclude admins from report
// NOTE: this is a dumb example because "where role != 'admin'" is better
// but every now and then you need to exclude stuff because of calculations
// that are a pain in sql and this is a contrived README
if columns[3] == "admin" {
return false, []string{}
}
extra_column_one = generateSomethingHypotheticalFromColumn(columns[2])
extra_column_two = lookupSomeApiThingForColumn(columns[4])
return append(columns, extra_column_one, extra_column_two)
})
csvConverter.WriteFile("~/important_user_report.csv")For more details on what else you can do to the Converter see the sqltocsv godocs
© John Barton but under MIT (see LICENSE) except for fakedb_test.go which I lifted from the Go standard library and is under BSD and I am unsure what that means legally.
