[英]What's wrong with sql?
我写的是 sql。
id="nana";
String queryNum = request.getParameter("id");
String query = "INSERT INTO likey (user, article) "
+"SELECT {"+id+"}, {"+queryNum+"} FROM reviews "
+"WHERE EXISTS ("
+"SELECT num FROM reviews WHERE num={"+queryNum+"}) "
+"AND NOT EXISTS("
+"SELECT num FROM likey WHERE user ={"+id+"}"
+"AND article ={"+id+"}) "
+"LIMIT 1";
System.out.println(query);
pstmt = con.prepareStatement(query);
out.println("111");
pstmt.executeUpdate();
out.println("2222");
但它不起作用。
我应该怎么办?
删除所有大括号:
String query = "INSERT INTO likey (user, article) "
+"SELECT "+id+", "+queryNum+" FROM reviews "
+"WHERE EXISTS ("
+"SELECT num FROM reviews WHERE num="+queryNum+") "
+"AND NOT EXISTS("
+"SELECT num FROM likey WHERE user ="+id
+"AND article ="+id+") "
+"LIMIT 1";
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