如何在androiddatabase中使用和运算符 [英] How to use and operator in androiddatabase

问题描述

我不知道为什么它不起作用。

它向我显示错误

附近=：语法错误（代码1）:,编译时：SELECT PASS，PASS FROM student_tableWHEREPASS ='CONTACT'ANDPASS =''
 

以下是DataBase类; 

  public  boolean loginstatus（ String  TABLE_NAME， String  COL_4， String  COL_5，字符串日志，字符串 pss）
 {
  try  {
 SQLiteDatabase db =  this  .getReadableDatabase（）; 
 Cursor cursor = db.rawQuery（  SELECT + COL_4 +  ， + COL_3 +   FROM + TABLE_NAME +   WHERE + COL_4 +   =' + log +  'AND + COL_3 +   =' + pss +  '， null ）; 
  if （cursor.moveToFirst（））
 {
} 

这是活动类

 log.setOnClickListener（ new  View.OnClickListener（）{
  @ Override  
  public   void  onClick（查看视图）{
 尝试 {
 
  boolean  recordExists = myDb.loginstatus（DatabaseOperation.TABLE_NAME，DatabaseOperation.COL_3，user.getText（）。toString（），DatabaseOperation.COL_4，us.getText（）。 toString（））; 
 
  if （recordExists）{

我尝试过：



现在我要添加AND operat或者我的code.so如何添加或如何实现此代码，这给出了语法错误的错误。

解决方案

空格......它们很重要。 ..

更改：

光标游标= db.rawQuery（  SELECT + COL_4 +  ， + COL_3 +   FROM + TABLE_NAME +  < span class =code-string> WHERE + COL_4 +   =' + log +  'AND + COL_3 +   =' + pss +  '，null）; 

要：

光标cursor = db.rawQuery（  SELECT + COL_4 +  ，  + COL_3 +   FROM + TABLE_NAME +    WHERE + COL_4 +   ='  + log +  'AND + COL_3 +   =' + pss +  '，NULL）; 

I don't know why it doesnot work.
It show me the error as

near "=": syntax error (code 1): , while compiling: SELECT PASS,PASS FROM student_tableWHEREPASS='CONTACT'ANDPASS=''

the following is the DataBase class;

public boolean loginstatus(String TABLE_NAME,String COL_4,String COL_5,String log,String pss)
   {
       try{
           SQLiteDatabase db=this.getReadableDatabase();
           Cursor cursor = db.rawQuery("SELECT "+ COL_4+ "," + COL_3+ " FROM "+TABLE_NAME+"WHERE"+COL_4+"='"+log+"'AND" +COL_3+ "='"+pss +"'",null);
           if (cursor.moveToFirst())
           {
}

and this is the activity class

log.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    try {
                       
                        boolean recordExists = myDb.loginstatus(DatabaseOperation.TABLE_NAME,DatabaseOperation.COL_3,user.getText().toString(),DatabaseOperation.COL_4,us.getText().toString());

                        if (recordExists) {

What I have tried:

now i want to add AND operator to my code.so how can i add or how i can implement this code which give the error of syntax error.

解决方案

Spaces...they are important...
Change:

Cursor cursor = db.rawQuery("SELECT "+ COL_4+ "," + COL_3+ " FROM "+TABLE_NAME+"WHERE"+COL_4+"='"+log+"'AND" +COL_3+ "='"+pss +"'",null);

To:

Cursor cursor = db.rawQuery("SELECT "+ COL_4+ "," + COL_3+ " FROM "+TABLE_NAME+" WHERE "+COL_4+"='"+log+"' AND " +COL_3+ "='"+pss +"'",null);

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