mysql sql parser support wait_n & no_wat

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/statement/MySqlSelectQueryBlock.java

@@ -47,6 +47,8 @@ public class MySqlSelectQueryBlock extends SQLSelectQueryBlock implements MySqlO
     private List<SQLExpr>        procedureArgumentList;
 
     private boolean              forUpdate       = false;
+    private boolean              noWait          = false;
+    private SQLExpr              waitTime;
     private boolean              lockInShareMode = false;
 
     private List<SQLCommentHint> hints;
@@ -81,6 +83,22 @@ public class MySqlSelectQueryBlock extends SQLSelectQueryBlock implements MySqlO
     public void setForUpdate(boolean forUpdate) {
         this.forUpdate = forUpdate;
     }
+    
+    public boolean isNoWait() {
+        return noWait;
+    }
+
+    public void setNoWait(boolean noWait) {
+        this.noWait = noWait;
+    }
+    
+    public SQLExpr getWaitTime() {
+        return waitTime;
+    }
+    
+    public void setWaitTime(SQLExpr waitTime) {
+        this.waitTime = waitTime;
+    }
 
     public boolean isLockInShareMode() {
         return lockInShareMode;

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlSelectParser.java

@@ -179,6 +179,15 @@ public class MySqlSelectParser extends SQLSelectParser {
             accept(Token.UPDATE);
 
             queryBlock.setForUpdate(true);
+            
+            if (identifierEquals("NO_WAIT")) {
+                lexer.nextToken();
+                queryBlock.setNoWait(true);
+            } else if (identifierEquals("WAIT")) {
+                lexer.nextToken();
+                SQLExpr waitTime = this.exprParser.primary();
+                queryBlock.setWaitTime(waitTime);
+            }
         }
 
         if (lexer.token() == Token.LOCK) {

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlOutputVisitor.java

@@ -287,6 +287,12 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         if (x.isForUpdate()) {
             println();
             print0(ucase ? "FOR UPDATE" : "for update");
+            if (x.isNoWait()) {
+                print0(ucase ? " NO_WAIT" : " no_wait");    
+            } else if (x.getWaitTime() != null) {
+                print0(ucase ? " WAIT " : " wait ");
+                x.getWaitTime().accept(this);
+            }
         }
 
         if (x.isLockInShareMode()) {