sql server - How to get data from multiple tables - 


    table1      <table>      <tr>      <td>id</td>      <td>name</td>      <td>rate</td>      </tr>       <tr>      <td>1</td>      <td>tomato</td>      <td>10</td>      </tr>       <tr>      <td>2</td>      <td>brinjal</td>      <td>10</td>      </tr>       <tr>      <td>3</td>      <td>potato</td>      <td>30</td>      </tr>       </table></br></br>      table2      <table>      <tr>      <td>id</td>      <td>new_rates</td>      </tr>       <tr>      <td>1</td>      <td>45</td>      </tr>         <tr>      <td>2</td>      <td>30</td>      </tr>           </table>      </br></br>      want result        <table>      <tr>      <td>id</td>      <td>name</td>      <td>rate</td>      </tr>       <tr>      <td>1</td>      <td>tomato</td>      <td>45</td>      </tr>       <tr>      <td>2</td>      <td>brinjal</td>      <td>30</td>      </tr>       <tr>      <td>3</td>      <td>potato</td>      <td>30</td>      </tr>       </table>

table 1

id   name      rate 1   tomato      10 2   brinjal     10 3   cucumber    30

table 2

id  new_rate 1   25

i want result 

id   name     rate 1   tomato     25 2   brinjal    10 3   cucumber   30 

select table1.id, table1.name,     isnull(table2.new_rate, table1.rate) rate   table1    left join table2 on table1.id = table2.id;

you need left outer join on second table because second table doesn't have matching rows rows in first table.

then can use isnull() function show value table 2, or if 1 doesn't exist show table 1.


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