Class Select

src/main/java/com/sql/parse/statement/impl/jsqlparser/Select.java:32–557

@date 2019年4月29日上午11:32:02 @desc Select语法操作类

 * @desc Select语法操作类
 */
public class Select extends com.sql.parse.statement.Select {
    private net.sf.jsqlparser.statement.select.Select select;

    public Select(net.sf.jsqlparser.statement.select.Select select) {
        this.select = select;
    }

    public Select(Table table) {
        this.select = SelectUtils.buildSelectFromTable(transformTable(table));
        isChangeColumn = true;
    }

    public Select(String tableName) {
        this(new Table(tableName));
    }

    /*public Select(Owner table, SelectItem... columns) {
        if(columns.length==0){
            this.select = SelectUtils.buildSelectFromTable(table.getTable());
        }else{
            SelectExpressionItem[] array = new SelectExpressionItem[columns.length];
            for (int i = 0; i < columns.length; i++) {
                array[i] = columns[i].getColumn();
            }
            this.select = SelectUtils.buildSelectFromTableAndSelectItems(table.getTable(), array);
        }
    }*/

    private net.sf.jsqlparser.schema.Table transformTable(Table table) {
        net.sf.jsqlparser.schema.Table t = new net.sf.jsqlparser.schema.Table(table.getTableName());
        if (table.getAlias() != null) {
            Alias alias = new Alias(table.getAlias(), table.isUseAs());
            t.setAlias(alias);
        }
        return t;
    }

    @Override
    public String getSql(boolean safe) {
        /*where条件为空时，添加[rownum<500]或[limit 500]的条件表达式*/
        Select mySelect = this.clone();
        PlainSelect plainSelect = (PlainSelect) mySelect.getSelect().getSelectBody();
        if (plainSelect.getLimit() == null) {
            boolean flag = true;
            List<net.sf.jsqlparser.statement.select.SelectItem> selectItems = plainSelect.getSelectItems();
            if (selectItems.size() == 1) {
                net.sf.jsqlparser.statement.select.SelectItem selectItem = selectItems.get(0);
                if (!(selectItem instanceof AllColumns)) {
                    Expression expression = ((SelectExpressionItem) selectItem).getExpression();
                    if (expression instanceof Function && "count".equals(((Function) expression).getName())) {
                        flag = false;
                    }
                }
            }
            if (plainSelect.getWhere() != null) {
                flag = false;
            }
            if (safe && flag) {