查询使用连接和字符串连接

Question

我是C＃的新手，来自VB6。任何人都可以看到为什么这个查询可能无法在C＃中工作？

command.CommandText = "SELECT " +
                      "S.idGroup, S.idStatement, P1.nameLast " +
                      "FROM " +
                      "STATEMENTS S, " +
                      "GROUPS G, " +
                      "PEOPLE P1, " +
                      "S LEFT JOIN G on G.id = S.idGroup, " +
                      "G LEFT JOIN P1 on P1.id = G.idContactPerson " +
                      "WHERE " +
                      "S.idTrip = @idTrip";

Answer 1

我认为你的SQL语法不正确，试试这个

"SELECT S.idGroup, S.idStatement, P1.nameLast " +
"FROM STATEMENTS S LEFT JOIN GROUPS G on G.id = S.idGroup " +
"LEFT JOIN People P1 on P1.id = G.idContactPerson " +
"WHERE S.idTrip = @idTrip";

Answer 2

Command.CommandText = @"SELECT S.idGroup, S.idStatement, P1.nameLast 
                      FROM STATEMENTS S LEFT JOIN GROUPS G on G.id = S.idGroup 
                      LEFT JOIN People P1 on P1.id = G.idContactPerson 
                      WHERE S.idTrip = " @idTrip;

试试这个语法！

Answer 3

如果你必须以这种方式构建SQL，请使用StringBuilder类来构建命令字符串。