我试图从表中的所有列中选择所有行并将它们输出到一个字符串,我尝试递增结果集并将每一行附加到一个字符串,但这没有用。
我让它工作的唯一方法是手动更改 resultset.getString() 但这只会显示 1 整行。
sql::Driver *driver;
sql::Connection *con;
sql::Statement *stmt;
sql::ResultSet *res;
/* Create a connection */
driver = get_driver_instance();
con = driver->connect("tcp://127.0.0.1:3306", "root", "root");
/* Connect to the MySQL test database */
con->setSchema("test");
stmt = con->createStatement();
res = stmt->executeQuery("SELECT 'Hello World!' AS _message");
while (res->next()) {
cout << "\t... MySQL replies: ";
/* Access column data by alias or column name */
cout << res->getString("_message") << endl;
cout << "\t... MySQL says it again: ";
/* Access column fata by numeric offset, 1 is the first column */
cout << res->getString(1) << endl;
}
正如您在倒数第二行看到的“cout << res->getString(1) << endl;”他们手动选择第一列。
是否可以选择所有列以便输出所有列中的所有行?
最佳答案
编辑:
最后,这会得到你所需要的......
sql::Driver *driver;
sql::Connection *con;
sql::Statement *stmt;
sql::ResultSet *res;
int main(int argc, const char *argv[]) {
/* Create a connection */
driver = get_driver_instance();
con = driver->connect("tcp://127.0.0.1:3306", "root", "root");
/* Connect to the MySQL so_test database */
con->setSchema("so_test");
stmt = con->createStatement();
// Select all columns/rows from example_table
res = stmt->executeQuery("SELECT * FROM example_table");
//get result set metadata
sql::ResultSetMetaData *res_meta = res -> getMetaData();
int columns = res_meta -> getColumnCount();
//Loop for each row
while (res->next()) {
/* Access column data by index, 1-indexed*/
for (int i = 1; i <= columns; i++) {
cout << res->getString(i) << "|" ;
}
cout << endl;
}
return 0;
}
不要忘记包含
#include <resultset_metadata.h>
关于c++ - mysql C++ 从所有列中选择所有行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34700277/