如何使用Golang在SQL中执行IN查找？

Question

Go想要这个SQL查询中的第二个参数.我试图IN在postgres中使用查找.

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);

Answer 1

查询只需要使用varargs来替换你的sql中的params,所以在你的例子中,你会这样做

rows, err := stmt.Query(10)

比如说,你和你的第二个例子是动态的,那么你就做了

stmt, err := db.Prepare("SELECT * FROM awesome_table WHERE id=$1 AND other_field IN ($2, $3)")
rows, err := stmt.Query(10,"this","that")

如果你有"IN"部分的变量args,你可以做(播放)

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)
}

Answer 2

看起来你可能正在使用pq驱动程序. pq最近通过pq.Array添加了Postgres特定的阵列支持(参见pull请求466).您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:

SELECT * FROM awesome_table WHERE id=10 AND other_field = ANY('{"this", "that"}');

请注意,这会使用预先准备好的语句,因此应对输入进行清理.

Answer 3

像我这样的人试图使用带查询的数组,这是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)

Answer 4

至少使用PostgreSQL,您可以使用单个占位符将整个数组作为字符串传递:

db.Query("select 1 = any($1::integer[])", "{1,2,3}")

这样,您可以使用单个查询字符串,并且所有字符串连接都仅限于参数.如果参数格式错误,则不会获得SQL注入; 你得到的结果如下:错误:整数的输入语法无效:"xyz"

https://groups.google.com/d/msg/golang-nuts/vHbg09g7s2I/RKU7XsO25SIJ

Answer 5

如果您使用sqlx，可以按照以下方式操作： https: //github.com/jmoiron/sqlx/issues/346

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...)