在这个SQL查询中，Go希望第二个参数是什么。
我正在尝试在Postgres中使用IN查找。
stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id= $1 AND other_field IN $2")
rows, err := stmt.Query(10, ???)
我真正想要的是：
SELECT * FROM awesome_table WHERE id=10 AND other_field IN (this, that);
看起来你可能正在使用pq驱动程序。最近，pq通过pq.Array添加了针对Postgres特定的数组支持（请参见 拉取请求 466）。你可以通过以下方式获得所需内容：
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'})
我认为这会生成SQL语句：
SELECT * FROM awesome_table WHERE id=10 AND other_field = ANY('{"this", "that"}');
请注意，这里使用了预处理语句，因此输入应该进行过滤。
查询只需使用varargs来替换SQL中的参数。因此，在您的示例中，您只需要执行以下操作：
rows, err := stmt.Query(10)
假设你的第二个示例中的这些内容是动态的，那么您需要执行以下操作：
stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id=$1 AND other_field IN ($2, $3)")
rows, err := stmt.Query(10,"this","that")
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)
}
stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id= $1 AND other_field IN $2")args:= []int{1,3,4,5}rows, err := stmt.Query(10, args) - a.m.strings.Join(strings.Split(strings.Repeat("?", len(stuff)), ""), ",")来替换一系列问号的构造。我觉得这样稍微少了一些思维负担。当然，你需要对空的stuff进行保护。 - harmwhere other_field = ANY($2) 然后传递 pq.StringArray(stuff)。这比计算 where 子句要好得多。 - David Budworth如果有人像我一样尝试在查询中使用数组，这里有一个简单的解决方案。
获取 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)
name := "foobar" q,args,err := sqlx.In("SELECT id,username FROM users WHERE id IN(?) AND name = (?);", ids, name) - eduncan911db.Query("select 1 = any($1::integer[])", "{1,2,3}")
https://groups.google.com/d/msg/golang-nuts/vHbg09g7s2I/RKU7XsO25SIJ
arr := []string{"this", "that"}
query, args, err := sqlx.In("SELECT * FROM awesome_table WHERE id=10 AND other_field IN (?)", arr)
query = db.Rebind(query) // sqlx.In returns queries with the `?` bindvar, rebind it here for matching the database in used (e.g. postgre, oracle etc, can skip it if you use mysql)
rows, err := db.Query(query, args...)
var awesome AwesomeStruct
var awesomes []*AwesomeStruct
ids := []int{1,2,3,4}
q, args, err := sqlx.In(`
SELECT * FROM awesome_table WHERE id=(?) AND other_field IN (?)`, 10, ids)
// use .Select for multiple return
err = db.Select(&awesomes, db.SQL.Rebind(q), args...)
// use .Get for single return
err = db.Get(&awesome, db.SQL.Rebind(q), args...)
//I tried a different way. A simpler and easier way, maybe not too efficient.
stringedIDs := fmt.Sprintf("%v", ids)
stringedIDs = stringedIDs[1 : len(stringedIDs)-1]
stringedIDs = strings.ReplaceAll(stringedIDs, " ", ",")
query := "SELECT * FROM users WHERE id IN (" + stringedIDs + ")"
//Then follow your standard database/sql Query
rows, err := db.Query(query)
//error checking
if err != nil {
// Handle errors
} else {
// Process rows
}
如果是服务器生成的，这个方法就比较普通了。其中UserIDs是一个字符串列表：
sqlc := `select count(*) from test.Logins where UserID
in ("` + strings.Join(UserIDs,`","`) + `")`
errc := db.QueryRow(sqlc).Scan(&Logins)
你也可以使用这种直接转换方法。
awesome_id_list := []int{3,5,8}
var str string
for _, value := range awesome_id_list {
str += strconv.Itoa(value) + ","
}
query := "SELECT * FROM awesome_table WHERE id IN (" + str[:len(str)-1] + ")"
警告
此方法容易受到SQL注入攻击。仅在awesome_id_list由服务器生成时使用此方法。