Question

String jk = "where nam='" + txt1.getText() + "'";
String ik = "and password='" + txt2.getPassword() + " ' ";
String sql;
sql = "SELECT * FROM Table1" + jk + ik;
rs = stmt.executeQuery(sql);

错误一直发生在from子句中的语法错误。

Answer 1

请尝试以下操作：

String jk =" where nam='"+txt1.getText()+"'";        //note the space before where
String ik =" and password='"+txt2.getPassword()+" '  //and space before and
String sql;                 
sql = "SELECT * FROM Table1" +jk+ik;                        
rs = stmt.executeQuery(sql);

最初您的查询如下所示

SELECT * FROM Table1where nam='xyz'and password='xyz';

空格后

SELECT * FROM Table1 where nam='xyz' and password='xyz';

Answer 2

为避免将来出现此类错误，我可以推荐PreparedStatement。 Here是Oracle教程。

String stmnt = "SELECT * FROM Table1 WHERE nam=? and password=?;";
PreparedStatement pstmt = con.prepareStatement(stmnt);
pstmt.setString(1, txt1.getText());
pstmt.setString(2, txt2.getText());
ResultSet rs = pstmt.executeQuery();

Answer 3

当你将jk和jk与sql结合使用时，table name和where子句之间没有空格。这就是你得到错误的原因。在那里有一个空间

String jk =" where nam='"+txt1.getText()+"'";                
String ik =" and password='"+txt2.getPassword()+" ' ";                               String sql;                 
sql = "SELECT * FROM Table1" +jk+ik;                        
rs = stmt.executeQuery(sql);

Answer 4

jk和ik

之间必须有空格

sql = "SELECT * FROM Table1" +jk+" "+ik;

但最好还是了解准备好的陈述。

Answer 5

试试这个：

String jk =" where nam='"+txt1.getText()+"'";                
String ik =" and password='"+txt2.getPassword()+" ' ";                                              

    String sql;                 
sql = "SELECT * FROM Table1" +jk+ik;                        
rs = stmt.executeQuery(sql);

您忘记在“where”和“and”之间添加空格另外我觉得nam将在表格列中命名

Answer 6

在from和where子句之间添加空格。

String jk ="where nam='"+txt1.getText()+"'";
String ik ="and password='"+txt2.getPassword()+" ' "; String sql;
sql = "SELECT * FROM Table1" + " " + jk + " " + ik; rs = stmt.executeQuery(sql);

Answer 7

String jk =" where nam='"+txt1.getText()+"' ";
String ik ="and password='"+txt2.getPassword()+"'";     
String sql = "SELECT * FROM Table1" +jk+ik;                        
rs = stmt.executeQuery(sql);

这应该可以正常工作..！欢呼快乐的编码.. :)

错误：来自if子句的语法错误

7 个答案: