How to execute an IN lookup in SQL using Golang?
What does Go want for the second param in this SQL query.
I am trying to use the IN
lookup in postgres.
stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id= $1 AND other_field IN $2")
rows, err := stmt.Query(10, ???)
What I really want:
SELECT * FROM awesome_table WHERE id=10 AND other_field IN (this, that);
Solution 1:
It looks like you may be using the pq driver. pq
recently added Postgres-specific Array support via pq.Array (see pull request 466). You can get what you want via:
stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id= $1 AND other_field = ANY($2)")
rows, err := stmt.Query(10, pq.Array([]string{'this','that'})
I think this generates the SQL:
SELECT * FROM awesome_table WHERE id=10 AND other_field = ANY('{"this", "that"}');
Note this utilizes prepared statements, so the inputs should be sanitized.
Solution 2:
Query just takes varargs to replace the params in your sql so, in your example, you would just do
rows, err := stmt.Query(10)
say, this and that of your second example were dynamic, then you'd do
stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id=$1 AND other_field IN ($2, $3)")
rows, err := stmt.Query(10,"this","that")
If you have variable args for the "IN" part, you can do (play)
package main
import "fmt"
import "strings"
func main() {
stuff := []interface{}{"this", "that", "otherthing"}
sql := "select * from foo where id=? and name in (?" + strings.Repeat(",?", len(stuff)-1) + ")"
fmt.Println("SQL:", sql)
args := []interface{}{10}
args = append(args, stuff...)
fakeExec(args...)
// This also works, but I think it's harder for folks to read
//fakeExec(append([]interface{}{10},stuff...)...)
}
func fakeExec(args ...interface{}) {
fmt.Println("Got:", args)
}
Solution 3:
Incase anyone like me was trying to use an array with a query, here is an easy solution.
get https://github.com/jmoiron/sqlx
ids := []int{1, 2, 3}
q,args,err := sqlx.In("SELECT id,username FROM users WHERE id IN(?);", ids) //creates the query string and arguments
//you should check for errors of course
q = sqlx.Rebind(sqlx.DOLLAR,q) //only if postgres
rows, err := db.Query(q,args...) //use normal POSTGRES/ANY SQL driver important to include the '...' after the Slice(array)