我是Go的新手，并且正在嘗試根據postgresql數據庫中的用戶名檢查密碼。我無法讓美元替換發生，寧愿不訴諸于連接字符串。我目前正在使用松鼠，但也嘗試過，沒有，沒有太多的運氣。我有以下代碼：    package datalayerimport (    "database/sql"    "encoding/json"    "fmt"    "net/http"    sq "github.com/Masterminds/squirrel"    _ "github.com/jackc/pgx/v4/stdlib"    "golang.org/x/crypto/bcrypt"    "github.com/gin-gonic/gin")var (    // for the database    db *sql.DB)func InitDB(sqlDriver string, dataSource string) error {    var err error    // Connect to the postgres db  (sqlDriver is literal string "pgx")    db, err = sql.Open(sqlDriver, dataSource)    if err != nil {        panic(err)    }    return db.Ping()}// Create a struct that models the structure of a user, both in the request body, and in the DBtype Credentials struct {    Password string `json:"password", db:"password"`    Username string `json:"username", db:"username"`}func Signin(c *gin.Context) {    // Parse and decode the request body into a new `Credentials` instance    creds := &Credentials{}    err := json.NewDecoder(c.Request.Body).Decode(creds)    if err != nil {        // If there is something wrong with the request body, return a 400 status        c.Writer.WriteHeader(http.StatusBadRequest)        return    }    query := sq.        Select("password").        From("users").        Where("username = $1", creds.Username).        PlaceholderFormat(sq.Dollar)        // The line below doesn't substitute the $ sign, it shows this:  SELECT password FROM users WHERE username = $1 [rgfdgfd] <nil>    fmt.Println(sq.        Select("password").        From("users").        Where("username = $1", creds.Username).        PlaceholderFormat(sq.Dollar).ToSql())    rows, sqlerr := query.RunWith(db).Query()    if sqlerr != nil {        panic(fmt.Sprintf("QueryRow failed: %v", sqlerr))    }    if err != nil {        // If there is an issue with the database, return a 500 error        c.Writer.WriteHeader(http.StatusInternalServerError)        return    }  當我檢查pgAdmin時，我看到以下內容，顯示美元符號未被替換：