SELECT CONCAT('Hello','World') 字符连接 FROM DUAL; --3,求字母串中的某个子串 SELECT SUBSTR('Hello World',3) FROM DUAL; --截取从第3个字符到末尾 SELECT SUBSTR('Hello World',3,4) FROM DUAL; --截取从第3个字符连续4个字符 --4,字符数和字节数 SELECT LENGTH('China') 字符数, LENGTHB('...
SQL> SELECT ROUND(45.923,2), ROUND(45.923,0), 2 ROUND(45.923,-1) 3 FROM SYS.DUAL; 四、ORACLE 日期格式和日期型函数: 1、默认格式为DD-MON-YY. 2、SYSDATE是一个求系统时间的函数 3、DUAL['dju:el] 是一个伪表,有人称之为空表,但不确切。 SQL> SELECT SYSDATE 2 FROM SYS.DUAL; 4、日期...
SELECT BITAND(6,3) FROM DUAL; BITAND(6,3) --- 2 SELECT BITAND( BIN_TO_NUM(1,1,0), BIN_TO_NUM(0,1,1)) "Binary" FROM DUAL; Binary --- 2 PostgreSQL BIT_TO_NUM PostgreSQL的bit转换为整型有隐式的转换,与显示的转换。 固定长度的bit到整型是可以使用隐式转换的,而varbit到整型则需要...
getchildnodes(domNode); select dbms_xmldom.getlength(nodeList) INTO v_getlenght from dual; dbms_output.put_line('v_getlenght = '||to_char(v_getlenght)); END; You get the following output. In order to call the DBMS_XMLDOM.GETLENGTH function in PostgreSQL, we have to...
Users can substitute the functionally equivalent “DISTINCT” keyword. Usage (ORACLE): SELECT UNIQUE deptid FROM dept; Workaround (PostgreSQL): SELECT DISTINCT deptid FROM dept; DUAL Table DUAL table is a dummy table used by Oracle, as for every select statement a FROM clause is mandatory. In...
SELECT ID, TRANSACTION_ID::text, EVENT_TYPE, JSON_DATA FROM ES_EVENT WHERE AGGREGATE_ID = :aggregateId AND (:fromVersion IS NULL OR VERSION > :fromVersion) AND (:toVersion IS NULL OR VERSION <= :toVersion) ORDER BY VERSION ASC Synchronously updating projections Using PostgreSQL as an eve...
The previous section demonstrated how to migrate PL/SQL code using the BULK COLLECT feature with FETCH to its equivalent constructs in PL/pgSQL. Now let’s explore the different aspects of the BULK COLLECT mechanism and the steps required to migrate using a SELECT state...
Select one or more objects from theSource Objectssection and click theicon to move the objects to theSelected Objectssection. Note You can select tables as the objects to be synchronized. Selected Objects To rename an object that you want to synchronize to t...
The program will traverse the data set until the callback function returns false. If the callback function has no return value, it is equivalent to returning true. db.query("select * from test where id=?", id, [](uint32_tid,conststd::string& name,constqtl::mysql::time& create_time...
SQL> (select‘dbtimezone’asconfig, dbtimezoneasoffsetfromdual) union(select‘sessiontimezone’asconfig, sessiontimezoneasoffsetfromdual);CONFIG OFFSET--- ---dbtimezone +00:00sessiontimezone +05:30SQL>selectsysdatefromdual;SYSDATE 03/01/202009:56:53SQL> alter sessionsettime_zone = ‘-...