/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.druid.sql.oracle.demo;

import com.alibaba.druid.sql.SQLUtils;
import com.alibaba.druid.sql.ast.SQLStatement;
import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlOutputVisitor;
import com.alibaba.druid.sql.parser.SQLStatementParser;
import com.alibaba.druid.util.JdbcConstants;
import junit.framework.TestCase;

import java.util.List;

public class Demo_casewhen extends TestCase {
    public void test_demo_0() throws Exception {
        String sql = "select case when a = 20 then b else c end from emp";

        // parser得到AST
        List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, JdbcConstants.ORACLE);

        SQLSelectStatement stmt = (SQLSelectStatement) stmtList.get(0);

        SQLCaseExpr caseExpr = (SQLCaseExpr) stmt.getSelect().getQueryBlock()
                .getSelectList().get(0).getExpr();
        System.out.println(caseExpr.getItems());
    }
}
