Cast a timestamp to date in a "where" clause

Hi everybody :)
I've got a little problem that seems very simple, but I can't solved it myself :(
I've got a column with a "timestamp" format, and I'd like to select all the records that are from a precise date, let's say "12/14/2009".
I have the following SQL statement :
SELECT * FROM myTable WHERE (CAST (myTimestampField AS DATE))= TO_DATE('12/14/2009', 'mm/dd/yyyy')
But that returns me nothing... However, I've got records with timestamps that where created the 14th of december.
Can you help me with that, I'm really out of ideas... And I'm not a SQL expert :p
Thanks a lot!

what is the bbcode for the code ? simple code ?write before and after your code snippet.
Max
[My Italian Oracle blog|http://oracleitalia.wordpress.com/2010/01/02/query-gerarchiche/]

Similar Messages

Performance with dates in the where clause

Performance with dates in the where clause
CREATE TABLE TEST_DATA
FNUMBER NUMBER,
FSTRING VARCHAR2(4000 BYTE),
FDATE DATE
create index t_indx on test_data(fdata);
query 1: select count(*) from TEST_DATA where trunc(fdate) = trunc(sysdate);
query 2: select count(*) from TEST_DATA where fdate between trunc(sysdate) and trunc(SYSDATE) + .99999;
query 3: select count(*) from TEST_DATA where fdate between to_date('21-APR-10', 'dd-MON-yy') and to_date('21-APR-10 23:59:59', 'DD-MON-YY hh24:mi:ss');
My questions:
1) Why isn't the index t_indx used in Execution plan 1?
2) From the execution plan, I see that query 2 & 3 is better than query 1. I do not see any difference between execution plan 2 & 3. Which one is better?
3) I read somewhere - "Always check the Access Predicates and Filter Predicates of Explain Plan carefully to determine which columns are contributing to a Range Scan and which columns are merely filtering the returned rows. Be sceptical if the same clause is shown in both."
Is that true for Execution plan 2 & 3?
3) Could some one explain what the filter & access predicate mean here?
Thanks in advance.
Execution Plan 1:
SQL> select count(*) from TEST_DATA where trunc(fdate) = trunc(sysdate);
COUNT(*)
283
Execution Plan
Plan hash value: 1486387033
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1 | 9 | 517 (20)| 00:00:07 |
| 1 | SORT AGGREGATE | | 1 | 9 | | |
|* 2 | TABLE ACCESS FULL| TEST_DATA | 341 | 3069 | 517 (20)| 00:00:07 |
Predicate Information (identified by operation id):
2 - filter(TRUNC(INTERNAL_FUNCTION("FDATE"))=TRUNC(SYSDATE@!))
Note
- dynamic sampling used for this statement
Statistics
4 recursive calls
0 db block gets
1610 consistent gets
0 physical reads
0 redo size
412 bytes sent via SQL*Net to client
380 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
Execution Plan 2:
SQL> select count(*) from TEST_DATA where fdate between trunc(sysdate) and trunc(SYSDATE) + .99999;
COUNT(*)
283
Execution Plan
Plan hash value: 1687886199
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1 | 9 | 3 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 9 | | |
|* 2 | FILTER | | | | | |
|* 3 | INDEX RANGE SCAN| T_INDX | 283 | 2547 | 3 (0)| 00:00:01 |
Predicate Information (identified by operation id):
2 - filter(TRUNC(SYSDATE@!)<=TRUNC(SYSDATE@!)+.9999884259259259259259
259259259259259259)
3 - access("FDATE">=TRUNC(SYSDATE@!) AND
"FDATE"<=TRUNC(SYSDATE@!)+.999988425925925925925925925925925925925
9)
Note
- dynamic sampling used for this statement
Statistics
7 recursive calls
0 db block gets
76 consistent gets
0 physical reads
0 redo size
412 bytes sent via SQL*Net to client
380 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows
Execution Plan 3:
SQL> select count(*) from TEST_DATA where fdate between to_date('21-APR-10', 'dd-MON-yy') and to_dat
e('21-APR-10 23:59:59', 'DD-MON-YY hh24:mi:ss');
COUNT(*)
283
Execution Plan
Plan hash value: 1687886199
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1 | 9 | 3 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 9 | | |
|* 2 | FILTER | | | | | |
|* 3 | INDEX RANGE SCAN| T_INDX | 283 | 2547 | 3 (0)| 00:00:01 |
Predicate Information (identified by operation id):
2 - filter(TO_DATE('21-APR-10','dd-MON-yy')<=TO_DATE('21-APR-10
23:59:59','DD-MON-YY hh24:mi:ss'))
3 - access("FDATE">=TO_DATE('21-APR-10','dd-MON-yy') AND
"FDATE"<=TO_DATE('21-APR-10 23:59:59','DD-MON-YY hh24:mi:ss'))
Note
- dynamic sampling used for this statement
Statistics
7 recursive calls
0 db block gets
76 consistent gets
0 physical reads
0 redo size
412 bytes sent via SQL*Net to client
380 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed

Hi,
user10541890 wrote:
Performance with dates in the where clause
CREATE TABLE TEST_DATA
FNUMBER NUMBER,
FSTRING VARCHAR2(4000 BYTE),
FDATE DATE
create index t_indx on test_data(fdata);Did you mean fdat<b>e</b> (ending in e)?
Be careful; post the code you're actually running.
query 1: select count(*) from TEST_DATA where trunc(fdate) = trunc(sysdate);
query 2: select count(*) from TEST_DATA where fdate between trunc(sysdate) and trunc(SYSDATE) + .99999;
query 3: select count(*) from TEST_DATA where fdate between to_date('21-APR-10', 'dd-MON-yy') and to_date('21-APR-10 23:59:59', 'DD-MON-YY hh24:mi:ss');
My questions:
1) Why isn't the index t_indx used in Execution plan 1?To use an index, the indexed column must stand alone as one of the operands. If you had a function-based index on TRUNC (fdate), then it might be used in Query 1, because the left operand of = is TRUNC (fdate).
2) From the execution plan, I see that query 2 & 3 is better than query 1. I do not see any difference between execution plan 2 & 3. Which one is better?That depends on what you mean by "better".
If "better" means faster, you've already shown that one is about as good as the other.
Queries 2 and 3 are doing different things. Assuming the table stays the same, Query 2 may give different results every day, but the results of Query 3 will never change.
For clarity, I prefer:
WHERE fdate >= TRUNC (SYSDATE)
AND fdate < TRUNC (SYSDATE) + 1(or replace SYSDATE with a TO_DATE expression, depending on the requirements).
3) I read somewhere - "Always check the Access Predicates and Filter Predicates of Explain Plan carefully to determine which columns are contributing to a Range Scan and which columns are merely filtering the returned rows. Be sceptical if the same clause is shown in both."
Is that true for Execution plan 2 & 3?
3) Could some one explain what the filter & access predicate mean here?Sorry, I can't.

PreparedStatement.setDate(int, Date) problem in WHERE clause

Hello all,
First and foremost, thanks for the help. It is really appreciated.
I am having the toughest time tracking down a problem with how I am handling date setting with my PreparedStatement. The kicker is that I am only having problems with the where clause date sets.
The date is pulled out of the database, put into a string, modified, put back into a date, and then used to query via SQL.
Data selected this way:
"SELECT * FROM table_name"
Data updated this way:
"UPDATE table_name SET name = ? WHERE pk_id = ? AND pk_date = ?"
The java.sql.Date object I use to PreparedStatement.setDate(int, Date) is exact to seconds. It works great if it is not in the where clause (eg Inserts work, Updates work without where clause) which leads me to believe there is truncation of data somewhere between setDate(int, Date) and the native SQL in Oracle 9i.
Is that a correct assumption? How do I solve this?
Thanks,
John

My assumption was correct. If a java.sql.DATE is pulled from a Oracle 9i database it may have more data in it than is allowed for in java.sql.Date. java.sql.Timestamp, on the other hand, does retain all data in the field.
The correct code looks something like this
prepStmt.setTimestamp(Timestamp.valueOf(timeString));
cheers,
John

Date functions in WHERE clause? HELP

The following two queries are identical except for how I supply the date values in the where clause, yet the first query using the a custom my_date function runs 30x slower than the one using the TO_DATE() function. Both return DATE types...any reason for the difference?
SELECT * from outcomes
WHERE start_time >=fn_my_date('START_MONTH')
AND start_time < fn_my_date('END_MONTH')+1
-- This runs 30x faster--
SELECT * from outcomes
WHERE start_time >=TO_DATE('08/01/2001','MM/DD/YYYY')
AND start_time < TO_DATE('08/31/2001','MM/DD/YYYY')+1
On the flip side, I've also experienced queries running slower using the TO_DATE() function vs the LAST_DAY(sysdate) for equivalenet dates.
null

I haven't seen the message coming up when using LENGTH or SUBSTR, but every time I connect to a database or attempt to change my preferences (including the "NLS Parameters: Comp" preference), this appears.
You are attempting to set the preference you should be to switch this from ANSI to something else, but SQL Developer is ignoring the preference setting (which I think is a bug).
A way to set the NLS_COMP to something else is to use something like "alter session set nls_comp = BINARY;". Note that changing any preference after that appears to overwrite this and you need to do this for each new connection you start.

How to use the MAX DATE condition in WHERE CLAUSE FILEDS

Hi,
I am trying to fetch the result for getting maximun date but when i try to execute the query i am getting the error as follows.
CONDITION : trunc(max(RD.DATERECEIVED)) BETWEEN TO_DATE('01/08/2011','DD/MM/YYYY') AND TO_DATE('01/08/2011','DD/MM/YYYY')
ERROR: Group function is not allowed here.
CHEERS,
PRABU AMMAIAPPAN

I see a couple of problems here.
First, what you posted below is not a syntactically valid query. It seems to be part of a larger query, specifically, this looks to be only the GROUP BY clause of a query.
Prabu ammaiappan wrote:
Hi,
I Have a group function in the Query. Below is the Query i have used it,
GROUP BY S.FREIGHTCLASS,
R.CONTAINERKEY,
S.SKU,
S.DESCR ||S.DESCRIPTION2,
S.PVTYPE,
RD.LOTTABLE06,
R.WAREHOUSEREFERENCE,
RD.TOLOC,
R.ADDWHO,
R.TYPE,
S.CWFLAG,
S.STDNETWGT,
S.ORDERUOM,
R.ADDDATE,
C.DESCRIPTION,
(CASE WHEN P.POKEY LIKE '%PUR%' THEN 'NULL' ELSE to_char(P.PODATE,'dd/mm/yyyy') END),
NVL((CASE WHEN R.ADDWHO='BOOMI' THEN RDD.SUPPLIERNAME END),SS.COMPANY),
RDD.BRAND,
S.NAPA,
RD.RECEIPTKEY,
R.SUSR4,
P.POKEY,
RDD.SUSR1,
r.STATUS, DECODE(RDD.SUSR2,' ',0,'',0,RDD.SUSR2),
rd.SUSR3Second, the answer to your primary question, "How do I add a predicate with with a MAX() function to my where clause?" is that you don't. As you discovered, if you attempt to do so, you'll find it doesn't work. If you stop and think about how SQL is processed, it should make sense to you why the SQL is not valid.
If you want to apply a filter condition such as:
trunc(max(RD.DATERECEIVED)) BETWEEN TO_DATE('01/08/2011','DD/MM/YYYY') AND TO_DATE('01/08/2011','DD/MM/YYYY')you should do it in a HAVING clause, not a where clause:
select ....
from ....
where ....
group by ....
having max(some_date) between this_date and that_date;Hope that helps,
-Mark

Date Range in Where clause

I have ssas DB with two cubes, they share the date dimension. My query shows users on the dimension and visit as a measure. In the where clause I have range of dates. I have this strange behavior that after a FULL cube process I don't see
any data when applying the range. I'm sure that I have data for the range because when I filter each day desperately I can see data. Another weird scenario is that if the date is on the dimension I can see data. The thing that solve it is when process DATA
the cubes. This my query:
select non empty [Users].[User].[User] columns,
{[Measures].[Visits]} on rows
from [System Visit] where
([Dim_Date].[Georgian Calendar].[Date ID].&[20150125]:[Dim_Date].[Georgian Calendar].[Date ID].&[20150202])
Any thoughts what can be the issue? Thanks

Hi liranbn,
According to your description, you want to return the Visits within a date range. Right?
In this scenario, please modify your MDX query like below:
select nonempty([Users].[User].[User].members,[Measures].[Visits]) on columns,
[Measures].[Visits] on rows
from [System Visit]
where
({[Dim_Date].[Georgian Calendar].[Date ID].&[20150125]:[Dim_Date].[Georgian Calendar].[Date ID].&[20150202]})
Please see MDX with AdventureWorks sample:
If you have any question, please feel free to ask.
Simon Hou
TechNet Community Support

Problem with date fields in where clause after changing driver

Hi,
We have changed the oracle driver we use to version 10
and now we have some trouble with date-fields.
When we run this SQL query from our Java program:
select *
from LA_TRANS
where LA_TRANS.FROM_DATE>='20040101' AND LA_TRANS.FROM_DATE<='20041231'
We get this error code:
ORA-01861: literal does not match format string
The query worked fine whit the previous driver.
Is there some way I can run a SQL query with date fields
as strings in the where clause?
Thanks!

Keeping the argument of standard SQL or not aside, comparing DATE columns to a constant string (which looks like a date in one of the thousands of the formats available, but not in others) is NOT one of the best programming practices and leads to heartburn and runtime errors (as you have seen yourself).
I would rather compare a DATE to a DATE.
Also, constants like that would be another issue to fix in your code:
http://asktom.oracle.com/pls/ask/f?p=4950:8:6899751034602146050::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:528893984337,

Query Builder won't apply chosen date to the where clause

Does anybody know why when I chose a date field, in the where clause, when using Query Builder, it won't actually write the chosen date to the actual query?
If I select the "View Query" tab, no date shows up. Also if I press the "Run Report" button in the "View Result" tab, I get this error:
"An error was encountered performing requested operation: ORA-00936: missing expression"
This is because actual date data is missing.
After I hit the "Apply" button, I have to manually type the date data.
I thought this was a bug of the previous version, but I just installed version 1.5.4 and I have no different result.
Thanks.

I just wanted to add my name to the list of people having this issue.
Oracle Techies, please help.

How to use DATE in the where clause

I need to select list of records from a table where available date is greater than or equal to current date. Below is the table structure and
select query used to get the list of records
CREATE TABLE TEMP (ITEM_ID NUMBER(20),ITEM_NAME VARCHAR2(100),CREATION_DATE DATE,AVAILABLE_DATE DATE);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(1,'ITEM1',SYSDATE,SYSDATE);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(2,'ITEM2',SYSDATE,SYSDATE+10);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(3,'ITEM3',SYSDATE,SYSDATE-10);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(4,'ITEM4',SYSDATE,SYSDATE);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(5,'ITEM5',SYSDATE,SYSDATE+5);
SELECT ITEM_NAME, available_date FROM TEMP WHERE available_date > SYSDATE OR available_date LIKE SYSDATE;I am getting the expected records but i am not able to find a condition where i can use *>=* for date data type, a query like the below one is
not returning expected records
SELECT ITEM_NAME, available_date FROM TEMP WHERE available_date >= SYSDATE ;Edited by: Balaji on Mar 19, 2012 9:13 PM

Hi,
Balaji wrote:
I need to select list of records from a table where available date is greater than or equal to current date. Below is the table structure and
select query used to get the list of records
CREATE TABLE TEMP (ITEM_ID NUMBER(20),ITEM_NAME VARCHAR2(100),CREATION_DATE DATE,AVAILABLE_DATE DATE);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(1,'ITEM1',SYSDATE,SYSDATE);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(2,'ITEM2',SYSDATE,SYSDATE+10);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(3,'ITEM3',SYSDATE,SYSDATE-10);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(4,'ITEM4',SYSDATE,SYSDATE);
INSERT INTO TEMP (ITEM_ID,ITEM_NAME,CREATION_DATE,AVAILABLE_DATE) VALUES(5,'ITEM5',SYSDATE,SYSDATE+5);
SELECT ITEM_NAME, available_date FROM TEMP WHERE available_date > SYSDATE OR available_date LIKE SYSDATE;
Both operands to LIKE are supposed to be strings. Don't try to use a DATE, such as SYSDATE, with LIKE.
I am getting the expected records but i am not able to find a condition where i can use *>=* for date data type, a query like the below one is
not returning expected records
SELECT ITEM_NAME, available_date FROM TEMP WHERE available_date >= SYSDATE ;
It's returning the results I expect.
If you'd say what results you were expecting, someone could help you wite a query to get them.
Assuming 1 second elapses between the time 'ITEM4' is inserted and the time the 2nd query is run, then, at run-time, available_date will be 1 second less than SYSDATE, so it should not be included.
If you want to find rows that are on the same calendar day as SYSDATE, or later, then use
WHERE available_date >= TRUNC (SYSDATE)

Date comparison in WHERE clause

I have this simple SQL sequence:
CREATE TABLE t1 (d1 DATE);
INSERT INTO t1 VALUES(CURRENT_DATE);
SELECT * FROM t1 WHERE d1 = CURRENT_DATE;
It is obvious what it does, yet on Oracle 10g R1 the SELECT query does not return anything. Any ideas on why this happens?
Thanks,
Robert

With me, everything works:
SQL> CREATE TABLE t11 (d1 DATE);
Tabel is aangemaakt.
SQL> INSERT INTO t11 VALUES(CURRENT_DATE);
1 rij is aangemaakt.
SQL> SELECT * FROM t11 WHERE d1 = CURRENT_DATE;
D1
24-10-2006 11:17:11
1 rij is geselecteerd.But this is because it is executed in a script.
It doesn't work with you because you are obviously unable to type the select statement within a second :-)
You probably forgot that the current_date has a time component with seconds too.
Regards,
Rob.

Date format in where clause

Hi,
I have a question. Our team was tuning a query where we needed to select a date column based solely on the month. We used between and it was very costly. Then we tried date_column_name = to_date('NOV-2002','MMM-YYYY') That sped it up considerably and it's returning the right rows. I just don't understand because I wouldn't have thought it would have met the = to criteria. I mean 11-20-2002 is not = to 'Nov-2002'. Does SQL automatically format the date column to match the format it is being compared to. I need to document this so if you can point me to documentation on it; I would greatly appreciate it.

I don't have an explanation for your question.
TO_DATE('NOV-2002','MON-YYYY') should return a date of November 1, 2002 at midnight. Perhaps you have records in your database which contain this date.
I would suggest changing your condition to use the 'BETWEEN' operator.
e.g.
WHERE date_column_name BETWEEN TO_DATE('11/01/2002','MM/DD/YYYY') AND TO_DATE('11/30/2002','MM/DD/YYYY')
Better yet, use some of the built-in date functions:
e.g.
WHERE date_column_name BETWEEN TRUNC(SYSDATE,'MON') AND LAST_DAY(SYSDATE)+1

How to use maximum date condition in where clause ?

Hi I want to check if SWITCH_FLAG has 'Y' for the latest batch run..how can write it?
(select a.SWITCH_FLAG
from MORTGAGE
where SYS_EFF_DATE = max(SYS_EFF_DATE)
) as expected_result
Error message:
ORA-00934: group function is not allowed here

This will give you the switch_flag for the latest eff_date,
SELECT SWITCH_FLAG
FROM (SELECT A.SWITCH_FLAG, ROW_NUMBER () OVER (ORDER BY SYS_EFF_DATE DESC) rn
FROM mortgage A)
WHERE rn = 1;
--if you want to test try this,
SELECT SWITCH_FLAG,SYS_EFF_DATE
FROM (SELECT A.SWITCH_FLAG,SYS_EFF_DATE , ROW_NUMBER () OVER (ORDER BY SYS_EFF_DATE DESC) rn
FROM mortgage A)
WHERE rn = 1;G.

Where clause and Dates

I am creating a coditional query for one of my data blocks.
What I need to do is build a where clause on the fly and pass
that back to my block using the Set_BLock_Property built in. I
am able to do this but I am having problems with the fact that I
don't know how to correctly pass a date back. It seems when
specifying a date in a where clause it needs to have single
quotes around this. But when ever I try to embed the quotes in
the string I am not successful. I have even tried appending the
quotes using the chr function doing something like.
Where_Clause := 'Birthday <= '

Spencer,
I think chr(39) will give you the correct character. For example,
Where_Clause := 'Birthday <= '

Date in where clause without Trunc

Hi,
How handle a date comparision in where clause without trunc. Rightnow I am using it with 'trunc', it is very slow..
Select ColumnA, ColumnB
From Sample
Where trunc(created_date,'DD-MON-YY') = '15-NOV-2011';
CREATE TABLE SAMPLE
     ColumnA NUMBER(9,0)           NOT NULL,
     ColumnB VARCHAR2(255)      NOT NULL,
     created_date                DATE
   );

Hi,
Here's one way:
SELECT ColumnA, ColumnB
FROM      Sample
WHERE      created_date     >= TO_DATE ('15-NOV-2011', 'DD-MON-YYYY')
AND     created_date     < TO_DATE ('15-NOV-2011', 'DD-MON-YYYY') + 1
;If you have an index on created_date. then this query will be able to use that index, because created_date is alone on one side of the operator.
Another reason why this will be faster is that it only has to call TO_DATE twice, regardless of how many rows are in the table. The original query had to call TRUNC for every row.
Don't compare a DATE (such as the results of TRUNC) to a string (such as '15-NOV-2011'). You're liable to get a run-time error, or, if youre not so lucky, unexpected results.
Edited by: Frank Kulash on Nov 15, 2011 5:22 PM

Where clause and order by to DAO classes

Hi
Is it ok(I mean design wise) to pass the 'where clause' conditions and order by clause as a parameter to the method of DAO class?

Well, I would suggest you write seperate methods in your dao , one to select data without the where clause and one to select data with the where clause thrown in. If you have different 'where' clauses for selecting different kinds of data, have that many dao methods. The dao methods being specific know exactly what is the data that's coming in.
Lets assume you have a list of purchase orders and each purchase order is indetified by a unique id called PURCHASE_ORDER_ID.
1. The following code would populate a purchase order's details given an id.
private statis final String QUERY_1 = "select * from PURCHASE_ORDERS where PURCHASE_ORDER_ID = ? ";
PurchaseOrderModel getPurchaseOrderData(long poId){
     //get a prepared statement from your connection
     PreparedStatement pst = conn.prepareStatement(QUERY_1);
     //set the poId passed as params to your query
     pst.setLong(1, poId);
     ResultSet rs = pst.executeQuery();
     if(rs.next()){
          //populate data into a model
     finally{
          //clean up resources
     return model;
}2. The following code would return a list of PurchaseOrderModel's whose shipping date falls between a set of dates selected by the user.
private statis final String QUERY_2 = "select * from PURCHASE_ORDERS where SHIPPING_DATE between ? and ? ";
PurchaseOrderModel getPurchaseOrdersBetweenDates(list bindValues){
     //get a prepared statement from your connection
     PreparedStatement pst = conn.prepareStatement(QUERY_1);
     //set the dates passed as params to your query
     //we know that the List ought to contain only 2 dates
     pst.setDate(1, (Date)bindValues.get(0));
     pst.setDate(2, (Date)bindValues.get(1));
     ResultSet rs = pst.executeQuery();
     if(rs.next()){
          //iterate and populate data into a model
          //add model to a list
     finally{
          //clean up resources
     return list;
     3. This is more interesting - the dao method searches a list of Purchase Orders starting with a set of specific words. The words themselves may be one or many. This means that the number of '?' in your prepared statement may be dynamic. Each element of the list is a String that contains the start substring of a purcahse order name. For example - the list may contain elements like ["a", "ab", "c", "gh"] and the dao method returns all purchase order starting with these names.
private statis final String QUERY_3 = "select * from PURCHASE_ORDERS where ";
PurchaseOrderModel getPurchaseOrderNameMatches(list bindValues){
     //construct the query dynamically
     StringBuffer query = new StringBuffer(QUERY_3);
     int count = 0;
     for(Iterator itr = bindValues.iterator(); itr.hasNext();;){
          String value = (String)itr.next();
          query.append ("name like 'value%' ");
          if (count != 0 and (count+1 != bindValues.length)){
               query.append(" or ");
          count ++;
     //get a prepared statement from your connection
     PreparedStatement pst = conn.prepareStatement(query.toString());
     ResultSet rs = pst.executeQuery();
     if(rs.next()){
          //iterate and populate data into a model
          //add model to a list
     finally{
          //clean up resources
     return list;
To sum up,
1. You need as many methods as you have different kinds of searches (one method for each kind of 'where' clause).
2. The ejb/business layer would examine the data and decide on which method to call.
3. Increases coding effort, but makes the code clean and readable. Each layer does it's job. Thus we dont have ejbs forming 'where' clauses and so on.
Having said that, it really is your decision - you should take into consideration the following factors -
1. How big is the project ? If its a huge codebase developed by many people, then segregate the responsibilities clearly in each layer as I have outlined. For a small scale project, you could go with your approach.
2. Whats the take on maintenance and future add-ons ? Do you see the codebase growing with time ?
3. Is your project a commercial one - is it a product that needs to be maintained or is it a one-off development - develop once and you are done with it.
4. What are the design considerations ? Is somebody going to audit code for quality ? Or is it a academic one ?
You should take into account all these before deciding to go one way or the other.
A general thumb rule should be that you should be convinced that your code readable (maintainable), scalable and efficient. Anything that you do towards these ends is good code/design despite what people/books/patterns say, IMO.
cheers,
ram.

Cast a timestamp to date in a "where" clause

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