<p>출처 :&nbsp;<a href="https://stackoverflow.com/questions/5528854/usage-of-mysqls-if-exists">https://stackoverflow.com/questions/5528854/usage-of-mysqls-if-exists</a></p><p><br></p><p>아래 쿼리와 같이 분기를 만들 수 있다.</p><p>다만 MySQL과 MariaDB에서는 function과 procedure에서만 아래와 같은 분기를 사용할 수 있다.</p><p><br></p><div style="color: rgb(212, 212, 212); background-color: rgb(30, 30, 30); font-family: Consolas, &quot;Courier New&quot;, monospace; font-size: 14px; line-height: 19px; white-space: pre;"><div><span style="color: #6a9955;">--&nbsp;MSSQL</span></div><div><span style="color: #569cd6;">IF</span>&nbsp;<span style="color: #569cd6;">EXISTS</span>&nbsp;(<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #b5cea8;">1</span>&nbsp;<span style="color: #569cd6;">FROM</span>&nbsp;TableName&nbsp;<span style="color: #569cd6;">WHERE</span>&nbsp;FieldValue&nbsp;=&nbsp;<span style="color: #ce9178;">''</span>)</div><div><span style="color: #569cd6;">BEGIN</span></div><div>&nbsp;&nbsp;&nbsp;&nbsp;<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #ce9178;">'있다'</span></div><div><span style="color: #569cd6;">END</span></div><div><span style="color: #569cd6;">ELSE</span></div><div><span style="color: #569cd6;">BEGIN</span></div><div>&nbsp;&nbsp;&nbsp;&nbsp;<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #ce9178;">'없다'</span></div><div><span style="color: #569cd6;">END</span></div><br><br><div><span style="color: #6a9955;">--&nbsp;MySQL을&nbsp;위해&nbsp;다시&nbsp;작성</span></div><div><span style="color: #569cd6;">IF</span>&nbsp;(<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #b5cea8;">1</span>&nbsp;=&nbsp;<span style="color: #b5cea8;">1</span>&nbsp;<span style="color: #569cd6;">FROM</span>&nbsp;TableName&nbsp;<span style="color: #569cd6;">WHERE</span>&nbsp;FieldValue&nbsp;=&nbsp;<span style="color: #ce9178;">''</span>)&nbsp;<span style="color: #569cd6;">THEN</span></div><div>&nbsp;&nbsp;&nbsp;&nbsp;<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #ce9178;">'있다'</span>;</div><div><span style="color: #569cd6;">ELSE</span></div><div>&nbsp;&nbsp;&nbsp;&nbsp;<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #ce9178;">'없다'</span>;</div><br><div><span style="color: #569cd6;">END</span>&nbsp;<span style="color: #569cd6;">IF</span>;</div><br><br><div><span style="color: #6a9955;">--&nbsp;아래는&nbsp;10.4.14-MariaDB-log&nbsp;버전에서&nbsp;확인한&nbsp;내용(이하&nbsp;버전에서는&nbsp;체크&nbsp;필요?)</span></div><div><span style="color: #6a9955;">--&nbsp;https://dba.stackexchange.com/questions/253724/unexpected-results-from-mariadb-if-exists-then</span></div><div><span style="color: #569cd6;">IF</span>&nbsp;<span style="color: #569cd6;">EXISTS</span>&nbsp;(<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #b5cea8;">1</span>&nbsp;<span style="color: #569cd6;">FROM</span>&nbsp;tcp_admin&nbsp;<span style="color: #569cd6;">WHERE</span>&nbsp;Id&nbsp;=&nbsp;iId&nbsp;<span style="color: #569cd6;">AND</span>&nbsp;IsEnable&nbsp;=&nbsp;<span style="color: #b5cea8;">0</span>)&nbsp;<span style="color: #569cd6;">THEN</span></div><div>&nbsp;&nbsp;&nbsp;&nbsp;<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #ce9178;">'있다'</span>;</div><div><span style="color: #569cd6;">ELSE</span></div><div>&nbsp;&nbsp;&nbsp;&nbsp;<span style="color: #569cd6;">SELECT</span>&nbsp;<span style="color: #ce9178;">'없다'</span>;</div><div><span style="color: #569cd6;">END</span>&nbsp;<span style="color: #569cd6;">IF</span>;</div></div><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p>


[MySQL & MariaDB] IF Exists 구문 활용하기