I want to insert MySQL database columns into [][]string in Go, here is a similar code which do this for only one column and insert it into []string but I need more columns into [][]string to make a data frame.
mysql> select * from users;
+----+-----------+----------+----------+-------------------------------+--------------+
| id | fname | lname | uname | email | contact |
+----+-----------+----------+----------+-------------------------------+--------------+
| 1 | Rishikesh | Agrawani | hygull | rishikesh0014051992@gmail.com | 917353787704 |
| 2 | Sandeep | E | sandeep | sandeepeswar8@gmail.com | 919739040038 |
| 3 | Darshan | Sidar | darshan | sidardarshan@gmail.com | 917996917565 |
| 4 | Surendra | Prajapat | surendra | surendrakgadwal@gmail.com | 918385894407 |
| 5 | Mukesh | Jakhar | mukesh | mjakhar.kjahhar@gmail.com | 919772254140 |
+----+-----------+----------+----------+-------------------------------+--------------+
5 rows in set (0.00 sec)
mysql>
func main() {
// db, err := sql.Open("mysql", "<username>:<password>@tcp(127.0.0.1:<port>)/<dbname>?charset=utf8" )
db, err := sql.Open("mysql", "hygull:admin@67@tcp(127.0.0.1:3306)/practice_db?charset=utf8")
if err != nil {
log.Fatal(err)
}
rows, err := db.Query("select fname from users")
if err != nil {
log.Fatal(err)
}
firstnames:=[]string{}
for rows.Next() {
var fname string
rows.Scan(&fname)
firstnames = append(firstnames, fname)
}
fmt.Println(firstnames)
db.Close()
}
Suppose your query returns 4 columns, you just scan multiple values at once.
details:=[][]string{}
for rows.Next() {
cols := make([]string, 4)
rows.Scan(&cols[0], &cols[1], &cols[2], &cols[3])
details = append(details, cols)
}
If the number of columns is not static, you can do something like this to automate it, instead of expanding the pointers manually:
details:=[][]string{}
for rows.Next() {
cols := make([]string, num_cols)
// Create an array of string pointers pointing to the column strings.
col_ptrs = make([]*string, num_cols)
for i := 0; i < num_cols; i++ {
col_ptrs[i] = &cols[i];
}
rows.Scan(col_ptrs...)
details = append(details, cols)
}