使用带有Postgres的Go sqlx包运行UPDATE查询时，是否可以检索更新的行的列表？

Question

I have a query I'm running using Go's sqlx package (an extension to the standard database/sql package) with a Postgres database. It looks something like this:

result, err := s.getDB(tx).Exec(`
    UPDATE table_name
    SET var_name = 0
    WHERE var_name = 1;`)
if err != nil {
    return nil, err
}

Without using a managed transaction, how can I retrieve the list of updated rows? Or at least a list of primary keys for the updated rows?

Answer 1

Use PostgreSQL's RETURNING clause and db.Query/db.Select variants instead of Exec, e.g.

//get the primary key of updated rows
db := s.getDB(tx)

results := []int{}
err = db.Select(&results, "UPDATE mytable SET var_name = 0 WHERE var_name = 1 RETURNING id")

To retrieve more than one columns, just list the column names after RETURNING, e.g.

rows, err := db.Queryx("UPDATE mytable SET var_name = 0 WHERE var_name = 1 RETURNING id,var_name,other_columns")
for rows.Next() {
    //do something with the result
}