diff --git a/src/main/scala/app/IndexController.scala b/src/main/scala/app/IndexController.scala
index 34631e1..1e71751 100644
--- a/src/main/scala/app/IndexController.scala
+++ b/src/main/scala/app/IndexController.scala
@@ -47,7 +47,7 @@
       case "issue" => if(query.isEmpty){
         search.html.issues(Nil, "", repository)
       } else {
-        search.html.issues(queryIssues(repository.owner, repository.name, query).map { case (issue, commentCount, content) =>
+        search.html.issues(searchIssuesByKeyword(repository.owner, repository.name, query).map { case (issue, commentCount, content) =>
           IssueSearchResult(
             issue.issueId,
             issue.title,
@@ -69,7 +69,7 @@
           treeWalk.setRecursive(true)
           treeWalk.addTree(revCommit.getTree)
 
-          val lowerQueries = StringUtil.splitWords(query.toLowerCase)
+          val keywords = StringUtil.splitWords(query.toLowerCase)
           val list = new ListBuffer[(String, (String, Int))]
           while (treeWalk.next()) {
             if(treeWalk.getFileMode(0) != FileMode.TREE){
@@ -77,7 +77,7 @@
                 if(FileUtil.isText(bytes)){
                   val text      = new String(bytes, "UTF-8")
                   val lowerText = text.toLowerCase
-                  val indices   = lowerQueries.map(lowerText.indexOf _)
+                  val indices   = keywords.map(lowerText.indexOf _)
                   if(!indices.exists(_ < 0)){
                     list.append((treeWalk.getPathString, getHighlightText(text, query)))
                   }
@@ -99,14 +99,14 @@
   })
 
   private def getHighlightText(content: String, query: String): (String, Int) = {
-    val lowerQueries = StringUtil.splitWords(query.toLowerCase)
-    val lowerText    = content.toLowerCase
-    val indices      = lowerQueries.map(lowerText.indexOf _)
+    val keywords  = StringUtil.splitWords(query.toLowerCase)
+    val lowerText = content.toLowerCase
+    val indices   = keywords.map(lowerText.indexOf _)
 
     if(!indices.exists(_ < 0)){
       val lineNumber = content.substring(0, indices.min).split("\n").size - 1
       val highlightText = StringUtil.escapeHtml(content.split("\n").drop(lineNumber).take(5).mkString("\n"))
-        .replaceAll("(?i)(" + lowerQueries.map("\\Q" + _ + "\\E").mkString("|") +  ")",
+        .replaceAll("(?i)(" + keywords.map("\\Q" + _ + "\\E").mkString("|") +  ")",
         "<span style=\"background-color: yellow;\">$1</span>")
       (highlightText, lineNumber + 1)
     } else {
diff --git a/src/main/scala/service/IssuesService.scala b/src/main/scala/service/IssuesService.scala
index 3e7ed11..6256f64 100644
--- a/src/main/scala/service/IssuesService.scala
+++ b/src/main/scala/service/IssuesService.scala
@@ -236,13 +236,22 @@
       }
       .update (closed, currentDate)
 
-  def queryIssues(owner: String, repository: String, query: String): List[(Issue, Int, String)] = {
-    val lowerQueries = StringUtil.splitWords(query.toLowerCase)
+  /**
+   * Search issues by keyword.
+   *
+   * @param owner the repository owner
+   * @param repository the repository name
+   * @param query the keywords separated by whitespace.
+   * @return issues with comment count and matched content of issue or comment
+   */
+  def searchIssuesByKeyword(owner: String, repository: String, query: String): List[(Issue, Int, String)] = {
+    import scala.slick.driver.H2Driver.likeEncode
+    val keywords = StringUtil.splitWords(query.toLowerCase)
 
     // Search Issue
     val issues = Query(Issues).filter { t =>
-      lowerQueries.map { query =>
-        (t.title.toLowerCase like '%' + query + '%') || (t.content.toLowerCase like '%' + query + '%') // TODO escape!!!!
+      keywords.map { keyword =>
+        (t.title.toLowerCase like (s"%${likeEncode(keyword)}%", '^')) || (t.content.toLowerCase like (s"%${likeEncode(keyword)}%", '^'))
       } .reduceLeft { (a, b) =>
         a && b
       }
@@ -252,8 +261,8 @@
     val comments = Query(IssueComments).innerJoin(Issues).on { case (t1, t2) =>
       t1.byIssue(t2.userName, t2.repositoryName, t2.issueId)
     }.filter { case (t1, t2) =>
-      lowerQueries.map { query =>
-        t1.content.toLowerCase like '%' + query + '%' // TODO escape!!!!
+      keywords.map { query =>
+        t1.content.toLowerCase like (s"%${likeEncode(query)}%", '^')
       }.reduceLeft { (a, b) =>
         a && b
       }