<p><span style="color:#c0392b;">contents 테이블</span></p> <table cellpadding="1" cellspacing="1" style="width:500px;"><tbody><tr><td><span style="background-color:#1abc9c;">r_wr_id</span></td> <td>bo_table</td> <td>title</td> </tr><tr><td><span style="background-color:#1abc9c;">23</span></td> <td>free</td> <td> </td> </tr><tr><td><span style="background-color:#1abc9c;">45</span></td> <td>game</td> <td>'안해요'</td> </tr></tbody></table><p> </p> <p><span style="color:#d35400;">g5_write_free 테이블</span></p> <table cellpadding="1" cellspacing="1" style="width:500px;"><tbody><tr><td><span style="background-color:#1abc9c;">wr_id</span></td> <td>at_create</td> <td>subject</td> </tr><tr><td><span style="background-color:#1abc9c;">23</span></td> <td> </td> <td>'안녕하세요'</td> </tr><tr><td> </td> <td> </td> <td> </td> </tr></tbody></table><p> </p> <p><span style="color:#c0392b;">g5_write_game 테이블</span></p> <table cellpadding="1" cellspacing="1" style="width:500px;"><tbody><tr><td><span style="background-color:#1abc9c;">wr_id</span></td> <td>at_create</td> <td>subject</td> </tr><tr><td><span style="background-color:#1abc9c;">45</span></td> <td> </td> <td>'게임해요'</td> </tr><tr><td> </td> <td> </td> <td> </td> </tr></tbody></table><p> </p> <p><span style="color:#c0392b;">g5_write_notice 테이블</span></p> <table cellpadding="1" cellspacing="1" style="width:500px;"><tbody><tr><td><span style="background-color:#1abc9c;">wr_id</span></td> <td>at_create</td> <td>subject</td> </tr><tr><td><span style="background-color:#1abc9c;">53</span></td> <td> </td> <td>'공지사항입니다.'</td> </tr><tr><td> </td> <td> </td> <td> </td> </tr></tbody></table><p>SELECT *</p> <p>FROM contents AS C <br>LEFT JOIN g4_write_free AS F<br>ON (C.r_wr_id = F.wr_id) <br>LEFT JOIN g4_write_game AS G <br>ON (C.r_wr_id = G.wr_id) </p> <p>LEFT JOIN g4_write_notice AS N <br>ON (C.r_wr_id = N.wr_id) <br>WHERE C.r_bo_table = "free" OR C.r_bo_table = "game" OR C.r_bo_table = "notice"</p> <p> </p> <p> </p> <p> contents 테이블 기준으로 </p> <p>LEFT JOIN 해서 출력하는 SQL문입니다.</p> <p> </p> <p>매칭 경우는 contents 테이블의 r_wr_id 와 해당 테이블의 wr_id로 매칭하게 됩니다.</p> <p> </p> <p>문제는 만약 contents의 테이블의 title NULL 값이면</p> <p>해당 테이블 JOIN한 매칭된 subject 값을 가져올려고 합니다.</p> <p> </p> <p>반대로 contents의 테이블의title값이 있다면 그냥 여기서 가져올려고 합니다.</p> <p> </p> <p>일단 제가 고민한것은</p> <p> </p> <p>IFNULL(C.title, subject) AS title  </p> <p> 를 이용해서 할려고 하지만 </p> <p> </p> <p>JOIN 한게 3개 이상이라 이렇게는 안되네요 ㅠ,ㅠ</p> <p> </p> <p>혹시 좋은 방법은 없을까요?</p> <p> </p> <p> </p> <div style="clear:both;"></div>