使用PG gem和Ruby在插入语句中选择多个值

Question

你们能帮我这个忙吗？ 如果我直接在postgresql数据库中使用此db查询，则可以正常工作，但是在Ruby中使用PG gem时，它希望我在数组中有6个值，但是我想从SELECT语句中获取这些值。

我收到的错误消息是：

ERROR:  bind message supplies 1 parameters, but prepared statement "statement2" requires 6 (PG::ProtocolViolation)

这是使用PG gem的Ruby中的代码。

conn.prepare('statement2', 'INSERT INTO client_results (client_type, distance, hostname, serial_number, rssi, txrate) VALUES ($1, $2, $3, $4, $5, $6)')
conn.exec_prepared('statement2', ["SELECT client_type, distance_in_ft, hostname, serial_number, -65, 224 FROM test_clients WHERE eth_ipv4 = 192.168.0.1"])

有效的实际SQL如下所示：

INSERT INTO client_results (client_type, distance, hostname, serial_number, rssi, txrate) SELECT client_type, distance_in_ft, hostname, serial_number, -65, 224 FROM test_clients WHERE eth_ipv4 = '192.168.0.1';

Answer 1

res = conn.exec("SELECT client_type, distance_in_ft, hostname, serial_number, -65, 224 FROM test_clients WHERE eth_ipv4 = 192.168.0.1").first

conn.prepare('statement2', 'INSERT INTO client_results (client_type, distance, hostname, serial_number, rssi, txrate) VALUES ($1, $2, $3, $4, $5, $6)')
conn.exec_prepared('statement2', res.values)

或直接按原样运行查询：

conn.exec("INSERT INTO client_results (client_type, distance, hostname, serial_number, rssi, txrate) SELECT client_type, distance_in_ft, hostname, serial_number, -65, 224 FROM test_clients WHERE eth_ipv4 = '192.168.0.1'")