error: syntax error from if clause

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);

错误发生在 from 子句中的语法错误。

Answer 1

当您将 jk 和 ik 与 sql 组合时，table 名称和 where 子句之间没有 space。这就是你收到错误的原因。那里有规格

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 2

jk 和 ik

之间必须有一个空格

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

但是最好还是了解准备好的语句。

Answer 3

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);

最初您的查询看起来如下

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

空格后

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

Answer 4

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" 之间添加空格我也觉得 table 列

中的名字是 nam

Answer 5

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 6

为了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 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..！干杯快乐编码.. :)

error: syntax error from if clause

error: syntax error from if clause

java

odbc

jdbc