支持mysql create/alter列中包含charset的解析

src/main/java/com/alibaba/druid/sql/dialect/mysql/ast/expr/MySqlCharExpr.java

@@ -53,8 +53,9 @@ public class MySqlCharExpr extends SQLCharExpr implements MySqlExpr {
             buf.append(charset);
             buf.append(' ');
         }
-
-        super.output(buf);
+        if (super.text!=null){
+            super.output(buf);
+        }
 
         if (collate != null) {
             buf.append(" COLLATE ");

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

@@ -26,10 +26,21 @@ public class MySqlSQLColumnDefinition extends SQLColumnDefinition {
 
     private SQLExpr storage;
 
+    private SQLExpr charsetExpr;
+
+
     public MySqlSQLColumnDefinition(){
 
     }
 
+    public SQLExpr getCharsetExpr() {
+        return charsetExpr;
+    }
+
+    public void setCharsetExpr(SQLExpr charsetExpr) {
+        this.charsetExpr = charsetExpr;
+    }
+
     public boolean isAutoIncrement() {
         return autoIncrement;
     }

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

@@ -531,7 +531,19 @@ public class MySqlExprParser extends SQLExprParser {
             SQLExpr expr = this.expr();
             ((MySqlSQLColumnDefinition) column).setOnUpdate(expr);
         }
-
+        if (identifierEquals("CHARSET")) {
+            lexer.nextToken();
+            MySqlCharExpr charSetCollateExpr=new MySqlCharExpr();
+            charSetCollateExpr.setCharset(lexer.stringVal());
+            lexer.nextToken();
+            if (identifierEquals("COLLATE")) {
+                lexer.nextToken();
+                charSetCollateExpr.setCollate(lexer.stringVal());
+                lexer.nextToken();
+            }
+            ((MySqlSQLColumnDefinition) column).setCharsetExpr(charSetCollateExpr);
+            return parseColumnRest(column);
+        }
         if (identifierEquals("AUTO_INCREMENT")) {
             lexer.nextToken();
             if (column instanceof MySqlSQLColumnDefinition) {

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

@@ -309,6 +309,11 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         print(' ');
         x.getDataType().accept(this);
 
+        if (mysqlColumn != null && mysqlColumn.getCharsetExpr() != null) {
+            print(" CHARSET ");
+            mysqlColumn.getCharsetExpr().accept(this);
+        }
+
         for (SQLColumnConstraint item : x.getConstraints()) {
             print(' ');
             item.accept(this);