Question

我有数百个数据库查询，如下面的格式

select VERSION, INSTALL_TIME from M_DATABASE_HISTORY

我使用下面的正则表达式来获取列名，（它基于（，）逗号标记SELECT和FROM之间的字符串）

String[] columnNames= query.split(" [fF][rR][oO][mM] ")[0]
                           .split("[ ]*[sS][eE][lL][eE][cC][tT] ")[1]
                           .split("[ ]*,[ ]*");

此代码适用于上述查询。

然而，我在使用列名中的函数（如下面的MAP）时获取列名时遇到问题，当有4列时它返回8列名称

select A.SYSTEM_ID, DATABASE_NAME, HOST, MAP(VALID, 'TRUE', 'Active' , 'FALSE' , 'Inactive')  AS Current_Status  from M_LICENSE A, M_DATABASE B where A.SYSTEM_ID = B.SYSTEM_ID

输出我正在

0.]A.SYSTEM_ID
1.]DATABASE_NAME
2.]HOST
3.]MAP(VALID
4.]'TRUE'
5.]'Active'
6.]'FALSE'
7.]'Inactive')  AS Current_Status

预期输出

0.]A.SYSTEM_ID
1.]DATABASE_NAME
2.]HOST
3.]MAP(VALID,'TRUE','Active','FALSE','Inactive')  AS Current_Status 
OR
3.] Current_Status

有人可以帮我为此建立一个正则表达式吗？或者欢迎任何更好的方法。

提前致谢。

Answer 1

我最终编写了一个函数来验证我的Columnnames函数名称。如果我的columnName包含＆＃39;（＆＃39;括号，我会在下一列中显示，直到找到＆＃39;）＆＃39;支架

代码段：

public static void main(String[] args) throws IOException {
    String[] queries = {
            "select A.SYSTEM_ID, DATABASE_NAME, HOST, START_TIME, VERSION, HARDWARE_KEY, "
                    + "INSTALL_NO, SYSTEM_NO, PRODUCT_NAME, PRODUCT_LIMIT, PRODUCT_USAGE, START_DATE, EXPIRATION_DATE, "
                    + "LAST_SUCCESSFUL_CHECK, MAP(PERMANENT, 'TRUE', 'Yes' , 'FALSE' , 'No') PERMANENT, "
                    + "MAP(VALID, 'TRUE', 'Active' , 'FALSE' , 'Inactive')  AS Current_Status  from M_LICENSE A, "
                    + "M_DATABASE B where A.SYSTEM_ID = B.SYSTEM_ID",
            "SELECT 'USER' TYPE, TABLE_TYPE, count(1) VAL FROM SYS.M_TABLES WHERE SCHEMA_NAME IN (SELECT SCHEMA_NAME from SYS.SCHEMAS WHERE SCHEMA_OWNER NOT IN ('SYS','_SYS_REPO','SYSTEM','_SYS_AFL','SAPHSA','SAPHEA','_SYS_EPM','_SYS_STATISTICS')) GROUP BY TABLE_TYPE UNION SELECT 'USER' TYPE, 'TOTAL', count(1) VAL FROM SYS.M_TABLES WHERE SCHEMA_NAME IN (SELECT SCHEMA_NAME from SYS.SCHEMAS WHERE SCHEMA_OWNER NOT IN ('SYS','_SYS_REPO','SYSTEM','_SYS_AFL','SAPHSA','SAPHEA','_SYS_EPM','_SYS_STATISTICS')) UNION SELECT 'SYSTEM' TYPE, TABLE_TYPE, count(1) VAL FROM SYS.M_TABLES WHERE SCHEMA_NAME IN (SELECT SCHEMA_NAME from SYS.SCHEMAS WHERE SCHEMA_OWNER IN ('SYS','_SYS_REPO','SYSTEM','_SYS_AFL','SAPHSA','SAPHEA','_SYS_EPM','_SYS_STATISTICS')) GROUP BY TABLE_TYPE UNION SELECT 'SYSTEM' TYPE, 'TOTAL', count(1) VAL FROM SYS.M_TABLES WHERE SCHEMA_NAME IN (SELECT SCHEMA_NAME from SYS.SCHEMAS WHERE SCHEMA_OWNER IN ('SYS','_SYS_REPO','SYSTEM','_SYS_AFL','SAPHSA','SAPHEA','_SYS_EPM','_SYS_STATISTICS'))" };

    for (int x = 0; x < queries.length; x++) {

        String query = queries[x];

        String[] fields = query.split(" [fF][rR][oO][mM] ")[0].split("[ ]*[sS][eE][lL][eE][cC][tT] ")[1]
                .split("[ ]*,[ ]*");

        fields = validateColumnNames(fields);

        for (int my = 0; my < fields.length; my++) {
            System.out.println(my + ".]" + fields[my]);
        }
    }

}

//validator for column Names to check function. If my columnName contain a 
// '(' bracket I appeneded the next columns until i found a ')' bracket.
private static String[] validateColumnNames(String[] fields) {
    ArrayList<String> result = new ArrayList<>();
    boolean enter = false;
    String appendField = "";
    for (int i = 0; i < fields.length; i++) {
        String onefield = fields[i];

        if (!enter) {
            if (onefield.contains("(")) {
                appendField = onefield;
                enter = true;
            } else {
                result.add(onefield);
            }
        } else {
            if (onefield.contains(")")) {
                appendField = appendField + "," + onefield;
                result.add(appendField);
                enter = false;
                appendField = "";
            } else {
                appendField = appendField + "," + onefield;
            }
        }
    }
    String[] validColNames = new String[result.size()];
    validColNames = result.toArray(validColNames);

    return validColNames;
}

验证字符串（查询）以查看列名是否包含SQL函数

1 个答案: