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Code Issues Releases Wiki Activity

add PagerUtils

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This commit is contained in:
wenshao
2013-02-02 13:48:48 +08:00
parent f83f076200
commit 21b8a41f4f
3 changed files with 145 additions and 17 deletions
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src/main/java/com/alibaba/druid/sql/PagerUtils.java
+90 -16
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@@ -1,3 +1,18 @@
/*
* Copyright 1999-2011 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;
import java.util.List;
@@ -5,6 +20,7 @@ import java.util.List;
import com.alibaba.druid.sql.ast.SQLStatement;
import com.alibaba.druid.sql.ast.expr.SQLAggregateExpr;
import com.alibaba.druid.sql.ast.expr.SQLAllColumnExpr;
import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
import com.alibaba.druid.sql.ast.statement.SQLSelect;
import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
@@ -13,6 +29,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
import com.alibaba.druid.sql.ast.statement.SQLSubqueryTableSource;
import com.alibaba.druid.sql.ast.statement.SQLUnionQuery;
import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
import com.alibaba.druid.sql.dialect.oracle.ast.expr.OracleAggregateExpr;
import com.alibaba.druid.sql.dialect.oracle.ast.stmt.OracleSelectQueryBlock;
import com.alibaba.druid.sql.dialect.postgresql.ast.stmt.PGSelectQueryBlock;
@@ -35,15 +52,63 @@ public class PagerUtils {
}
SQLSelectStatement selectStmt = (SQLSelectStatement) stmt;
return count(selectStmt, dbType);
return count(selectStmt.getSelect(), dbType);
}
public static String limit(String sql, String dbType, int offset, int count) {
List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, dbType);
private static String count(SQLSelectStatement stmt, String dbType) {
SQLSelect select = stmt.getSelect();
if (stmtList.size() != 1) {
throw new IllegalArgumentException("sql not support count : " + sql);
}
SQLStatement stmt = stmtList.get(0);
if (!(stmt instanceof SQLSelectStatement)) {
throw new IllegalArgumentException("sql not support count : " + sql);
}
SQLSelectStatement selectStmt = (SQLSelectStatement) stmt;
return limit(selectStmt.getSelect(), dbType, offset, count);
}
public static String limit(SQLSelect select, String dbType, int offset, int count) {
SQLSelectQuery query = select.getQuery();
if (query instanceof SQLSelectQueryBlock) {
return limit((SQLSelectQueryBlock) query, dbType, offset, count);
}
throw new UnsupportedOperationException();
}
public static String limit(SQLSelectQueryBlock queryBlock, String dbType, int offset, int count) {
if (JdbcConstants.MYSQL.equals(dbType)) {
return limitMySql((MySqlSelectQueryBlock) queryBlock, dbType, offset, count);
}
throw new UnsupportedOperationException();
}
public static String limitMySql(MySqlSelectQueryBlock queryBlock, String dbType, int offset, int count) {
if (queryBlock.getLimit() != null) {
throw new IllegalArgumentException("limit already exists.");
}
Limit limit = new Limit();
if (offset > 0) {
limit.setOffset(new SQLNumberExpr(offset));
}
limit.setRowCount(new SQLNumberExpr(count));
queryBlock.setLimit(limit);
return SQLUtils.toSQLString(queryBlock, dbType);
}
private static String count(SQLSelect select, String dbType) {
if (select.getOrderBy() != null) {
select.setOrderBy(null);
}
SQLSelectQuery query = select.getQuery();
clearOrderBy(query);
@@ -51,26 +116,35 @@ public class PagerUtils {
SQLSelectItem countItem = createCountItem(dbType);
SQLSelectQueryBlock queryBlock = (SQLSelectQueryBlock) query;
if (queryBlock.getGroupBy() != null && queryBlock.getGroupBy().getItems().size() > 0) {
return createCountUseSubQuery(select, dbType);
}
queryBlock.getSelectList().clear();
queryBlock.getSelectList().add(countItem);
return SQLUtils.toSQLString(stmt, dbType);
return SQLUtils.toSQLString(select, dbType);
} else if (query instanceof SQLUnionQuery) {
SQLSelectQueryBlock countSelectQuery = createQueryBlock(dbType);
SQLSelectItem countItem = createCountItem(dbType);
countSelectQuery.getSelectList().add(countItem);
countSelectQuery.setFrom(new SQLSubqueryTableSource(select));
SQLSelect countSelect = new SQLSelect(countSelectQuery);
SQLSelectStatement countStmt = new SQLSelectStatement(countSelect);
return SQLUtils.toSQLString(countStmt, dbType);
return createCountUseSubQuery(select, dbType);
}
throw new IllegalStateException();
}
private static String createCountUseSubQuery(SQLSelect select, String dbType) {
SQLSelectQueryBlock countSelectQuery = createQueryBlock(dbType);
SQLSelectItem countItem = createCountItem(dbType);
countSelectQuery.getSelectList().add(countItem);
countSelectQuery.setFrom(new SQLSubqueryTableSource(select));
SQLSelect countSelect = new SQLSelect(countSelectQuery);
SQLSelectStatement countStmt = new SQLSelectStatement(countSelect);
return SQLUtils.toSQLString(countStmt, dbType);
}
private static SQLSelectQueryBlock createQueryBlock(String dbType) {
if (JdbcConstants.MYSQL.equals(dbType)) {
return new MySqlSelectQueryBlock();