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Druid/src/main/java/com/alibaba/druid/sql/PagerUtils.java
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/*
* 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;
import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.SQLOrderBy;
import com.alibaba.druid.sql.ast.SQLOver;
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.SQLBinaryOpExpr;
import com.alibaba.druid.sql.ast.expr.SQLBinaryOperator;
import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
import com.alibaba.druid.sql.ast.expr.SQLPropertyExpr;
import com.alibaba.druid.sql.ast.statement.SQLSelect;
import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
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.db2.ast.stmt.DB2SelectQueryBlock;
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.stmt.OracleSelectQueryBlock;
import com.alibaba.druid.sql.dialect.postgresql.ast.stmt.PGSelectQueryBlock;
import com.alibaba.druid.sql.dialect.postgresql.ast.stmt.PGSelectQueryBlock.PGLimit;
import com.alibaba.druid.sql.dialect.sqlserver.ast.SQLServerSelectQueryBlock;
import com.alibaba.druid.sql.dialect.sqlserver.ast.SQLServerTop;
import com.alibaba.druid.util.JdbcConstants;
import com.alibaba.druid.util.JdbcUtils;
public class PagerUtils {
public static String count(String sql, String dbType) {
List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, dbType);
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 count(selectStmt.getSelect(), dbType);
}
public static String limit(String sql, String dbType, int offset, int count) {
List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, dbType);
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 (JdbcConstants.ORACLE.equals(dbType)) {
return limitOracle(select, dbType, offset, count);
}
if (JdbcConstants.DB2.equals(dbType)) {
return limitDB2(select, dbType, offset, count);
}
if (JdbcConstants.SQL_SERVER.equals(dbType) || JdbcUtils.JTDS.equals(dbType)) {
return limitSQLServer(select, dbType, offset, count);
}
if (query instanceof SQLSelectQueryBlock) {
return limitQueryBlock(select, dbType, offset, count);
}
throw new UnsupportedOperationException();
}
private static String limitQueryBlock(SQLSelect select, String dbType, int offset, int count) {
SQLSelectQueryBlock queryBlock = (SQLSelectQueryBlock) select.getQuery();
if (JdbcConstants.MYSQL.equals(dbType) || //
JdbcConstants.MARIADB.equals(dbType) || //
JdbcConstants.H2.equals(dbType)) {
return limitMySqlQueryBlock((MySqlSelectQueryBlock) queryBlock, dbType, offset, count);
}
if (JdbcConstants.POSTGRESQL.equals(dbType))
{
return limitPostgreSQLQueryBlock((PGSelectQueryBlock) queryBlock, dbType, offset, count);
}
throw new UnsupportedOperationException();
}
private static String limitPostgreSQLQueryBlock(PGSelectQueryBlock queryBlock, String dbType,
int offset, int count) {
if (queryBlock.getLimit() != null)
{
throw new IllegalArgumentException("limit already exists.");
}
PGLimit limit = new PGLimit();
if (offset > 0)
{
limit.setOffset(new SQLNumberExpr(offset));
}
limit.setRowCount(new SQLNumberExpr(count));
queryBlock.setLimit(limit);
return SQLUtils.toSQLString(queryBlock, dbType);
}
private static String limitDB2(SQLSelect select, String dbType, int offset, int count) {
SQLSelectQuery query = select.getQuery();
SQLBinaryOpExpr gt = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
SQLBinaryOperator.GreaterThan, //
new SQLNumberExpr(offset), //
JdbcConstants.DB2);
SQLBinaryOpExpr lteq = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
SQLBinaryOperator.LessThanOrEqual, //
new SQLNumberExpr(count + offset), //
JdbcConstants.DB2);
SQLBinaryOpExpr pageCondition = new SQLBinaryOpExpr(gt, SQLBinaryOperator.BooleanAnd, lteq, JdbcConstants.DB2);
if (query instanceof SQLSelectQueryBlock) {
DB2SelectQueryBlock queryBlock = (DB2SelectQueryBlock) query;
if (offset <= 0) {
queryBlock.setFirst(new SQLNumberExpr(count));
return SQLUtils.toSQLString(select, dbType);
}
SQLAggregateExpr aggregateExpr = new SQLAggregateExpr("ROW_NUMBER");
SQLOrderBy orderBy = select.getOrderBy();
aggregateExpr.setOver(new SQLOver(orderBy));
select.setOrderBy(null);
queryBlock.getSelectList().add(new SQLSelectItem(aggregateExpr, "ROWNUM"));
DB2SelectQueryBlock countQueryBlock = new DB2SelectQueryBlock();
countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
countQueryBlock.setFrom(new SQLSubqueryTableSource(select, "XX"));
countQueryBlock.setWhere(pageCondition);
return SQLUtils.toSQLString(countQueryBlock, dbType);
}
DB2SelectQueryBlock countQueryBlock = new DB2SelectQueryBlock();
countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLPropertyExpr(new SQLIdentifierExpr("XX"), "*")));
SQLAggregateExpr aggregateExpr = new SQLAggregateExpr("ROW_NUMBER");
SQLOrderBy orderBy = select.getOrderBy();
aggregateExpr.setOver(new SQLOver(orderBy));
select.setOrderBy(null);
countQueryBlock.getSelectList().add(new SQLSelectItem(aggregateExpr, "ROWNUM"));
countQueryBlock.setFrom(new SQLSubqueryTableSource(select, "XX"));
if (offset <= 0) {
return SQLUtils.toSQLString(countQueryBlock, dbType);
}
DB2SelectQueryBlock offsetQueryBlock = new DB2SelectQueryBlock();
offsetQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
offsetQueryBlock.setFrom(new SQLSubqueryTableSource(new SQLSelect(countQueryBlock), "XXX"));
offsetQueryBlock.setWhere(pageCondition);
return SQLUtils.toSQLString(offsetQueryBlock, dbType);
}
private static String limitSQLServer(SQLSelect select, String dbType, int offset, int count) {
SQLSelectQuery query = select.getQuery();
SQLBinaryOpExpr gt = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
SQLBinaryOperator.GreaterThan, //
new SQLNumberExpr(offset), //
JdbcConstants.SQL_SERVER
);
SQLBinaryOpExpr lteq = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
SQLBinaryOperator.LessThanOrEqual, //
new SQLNumberExpr(count + offset), //
JdbcConstants.SQL_SERVER);
SQLBinaryOpExpr pageCondition = new SQLBinaryOpExpr(gt, SQLBinaryOperator.BooleanAnd, lteq, JdbcConstants.SQL_SERVER);
if (query instanceof SQLSelectQueryBlock) {
SQLServerSelectQueryBlock queryBlock = (SQLServerSelectQueryBlock) query;
if (offset <= 0) {
queryBlock.setTop(new SQLServerTop(new SQLNumberExpr(count)));
return SQLUtils.toSQLString(select, dbType);
}
SQLAggregateExpr aggregateExpr = new SQLAggregateExpr("ROW_NUMBER");
SQLOrderBy orderBy = select.getOrderBy();
aggregateExpr.setOver(new SQLOver(orderBy));
select.setOrderBy(null);
queryBlock.getSelectList().add(new SQLSelectItem(aggregateExpr, "ROWNUM"));
SQLServerSelectQueryBlock countQueryBlock = new SQLServerSelectQueryBlock();
countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
countQueryBlock.setFrom(new SQLSubqueryTableSource(select, "XX"));
countQueryBlock.setWhere(pageCondition);
return SQLUtils.toSQLString(countQueryBlock, dbType);
}
SQLServerSelectQueryBlock countQueryBlock = new SQLServerSelectQueryBlock();
countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLPropertyExpr(new SQLIdentifierExpr("XX"), "*")));
countQueryBlock.setFrom(new SQLSubqueryTableSource(select, "XX"));
if (offset <= 0) {
countQueryBlock.setTop(new SQLServerTop(new SQLNumberExpr(count)));
return SQLUtils.toSQLString(countQueryBlock, dbType);
}
SQLAggregateExpr aggregateExpr = new SQLAggregateExpr("ROW_NUMBER");
SQLOrderBy orderBy = select.getOrderBy();
aggregateExpr.setOver(new SQLOver(orderBy));
select.setOrderBy(null);
countQueryBlock.getSelectList().add(new SQLSelectItem(aggregateExpr, "ROWNUM"));
SQLServerSelectQueryBlock offsetQueryBlock = new SQLServerSelectQueryBlock();
offsetQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
offsetQueryBlock.setFrom(new SQLSubqueryTableSource(new SQLSelect(countQueryBlock), "XXX"));
offsetQueryBlock.setWhere(pageCondition);
return SQLUtils.toSQLString(offsetQueryBlock, dbType);
}
private static String limitOracle(SQLSelect select, String dbType, int offset, int count) {
SQLSelectQuery query = select.getQuery();
if (query instanceof SQLSelectQueryBlock) {
OracleSelectQueryBlock queryBlock = (OracleSelectQueryBlock) query;
if (queryBlock.getGroupBy() == null && select.getOrderBy() == null && offset <= 0) {
SQLExpr condition = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
SQLBinaryOperator.LessThanOrEqual, //
new SQLNumberExpr(count), //
JdbcConstants.ORACLE
);
if (queryBlock.getWhere() == null) {
queryBlock.setWhere(condition);
} else {
queryBlock.setWhere(new SQLBinaryOpExpr(queryBlock.getWhere(), //
SQLBinaryOperator.BooleanAnd, //
condition, //
JdbcConstants.ORACLE
));
}
return SQLUtils.toSQLString(select, dbType);
}
}
OracleSelectQueryBlock countQueryBlock = new OracleSelectQueryBlock();
countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLPropertyExpr(new SQLIdentifierExpr("XX"), "*")));
countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLIdentifierExpr("ROWNUM"), "RN"));
countQueryBlock.setFrom(new SQLSubqueryTableSource(select, "XX"));
countQueryBlock.setWhere(new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
SQLBinaryOperator.LessThanOrEqual, //
new SQLNumberExpr(count + offset), //
JdbcConstants.ORACLE));
if (offset <= 0) {
return SQLUtils.toSQLString(countQueryBlock, dbType);
}
OracleSelectQueryBlock offsetQueryBlock = new OracleSelectQueryBlock();
offsetQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
offsetQueryBlock.setFrom(new SQLSubqueryTableSource(new SQLSelect(countQueryBlock), "XXX"));
offsetQueryBlock.setWhere(new SQLBinaryOpExpr(new SQLIdentifierExpr("RN"), //
SQLBinaryOperator.GreaterThan, //
new SQLNumberExpr(offset), //
JdbcConstants.ORACLE));
return SQLUtils.toSQLString(offsetQueryBlock, dbType);
}
private static String limitMySqlQueryBlock(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);
if (query instanceof SQLSelectQueryBlock) {
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(select, dbType);
} else if (query instanceof SQLUnionQuery) {
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);
SQLSubqueryTableSource fromSubquery = new SQLSubqueryTableSource(select);
fromSubquery.setAlias("ALIAS_COUNT");
countSelectQuery.setFrom(fromSubquery);
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();
}
if (JdbcConstants.MARIADB.equals(dbType)) {
return new MySqlSelectQueryBlock();
}
if (JdbcConstants.H2.equals(dbType)) {
return new MySqlSelectQueryBlock();
}
if (JdbcConstants.ORACLE.equals(dbType)) {
return new OracleSelectQueryBlock();
}
if (JdbcConstants.POSTGRESQL.equals(dbType)) {
return new PGSelectQueryBlock();
}
if (JdbcConstants.SQL_SERVER.equals(dbType) || JdbcUtils.JTDS.equals(dbType)) {
return new SQLServerSelectQueryBlock();
}
if (JdbcConstants.DB2.equals(dbType)) {
return new DB2SelectQueryBlock();
}
return new SQLSelectQueryBlock();
}
private static SQLSelectItem createCountItem(String dbType) {
SQLAggregateExpr countExpr = new SQLAggregateExpr("COUNT");
countExpr.getArguments().add(new SQLAllColumnExpr());
SQLSelectItem countItem = new SQLSelectItem(countExpr);
return countItem;
}
private static void clearOrderBy(SQLSelectQuery query) {
if (query instanceof SQLSelectQueryBlock) {
SQLSelectQueryBlock queryBlock = (SQLSelectQueryBlock) query;
if (queryBlock instanceof MySqlSelectQueryBlock) {
MySqlSelectQueryBlock mysqlQueryBlock = (MySqlSelectQueryBlock) queryBlock;
if (mysqlQueryBlock.getOrderBy() != null) {
mysqlQueryBlock.setOrderBy(null);
}
} else if (queryBlock instanceof PGSelectQueryBlock) {
PGSelectQueryBlock pgQueryBlock = (PGSelectQueryBlock) queryBlock;
if (pgQueryBlock.getOrderBy() != null) {
pgQueryBlock.setOrderBy(null);
}
}
return;
}
if (query instanceof SQLUnionQuery) {
SQLUnionQuery union = (SQLUnionQuery) query;
if (union.getOrderBy() != null) {
union.setOrderBy(null);
}
clearOrderBy(union.getLeft());
clearOrderBy(union.getRight());
}
}
}
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