How to declare variable and use it in the same Oracle SQL script?

I want to write reusable code and need to declare some variables at the beginning and reuse them in the script, such as:

DEFINE stupidvar = 'stupidvarcontent';SELECT stupiddataFROM stupidtableWHERE stupidcolumn = &stupidvar;

How can I declare a variable and reuse it in statements that follow such as in using it SQLDeveloper.

Attempts

  • Use a DECLARE section and insert the following SELECT statement in BEGIN and END;. Acces the variable using &stupidvar.
  • Use the keyword DEFINE and access the variable.
  • Using the keyword VARIABLE and access the the variable.

But I am getting all kinds of errors during my tries (Unbound variable, Syntax error, Expected SELECT INTO...).

11

Best Answer

There are a several ways of declaring variables in SQL*Plus scripts.

The first is to use VAR, to declare a bind variable. The mechanism for assigning values to a VAR is with an EXEC call:

SQL> var name varchar2(20)SQL> exec :name := 'SALES'PL/SQL procedure successfully completed.SQL> select * from dept2 where dname = :name3 /DEPTNO DNAME LOC---------- -------------- -------------30 SALES CHICAGOSQL>

A VAR is particularly useful when we want to call a stored procedure which has OUT parameters or a function.

Alternatively we can use substitution variables. These are good for interactive mode:

SQL> accept p_dno prompt "Please enter Department number: " default 10Please enter Department number: 20SQL> select ename, sal2 from emp3 where deptno = &p_dno4 /old 3: where deptno = &p_dnonew 3: where deptno = 20ENAME SAL---------- ----------CLARKE 800ROBERTSON 2975RIGBY 3000KULASH 1100GASPAROTTO 3000SQL>

When we're writing a script which calls other scripts it can be useful to DEFine the variables upfront. This snippet runs without prompting me to enter a value:

SQL> def p_dno = 40SQL> select ename, sal2 from emp3 where deptno = &p_dno4 /old 3: where deptno = &p_dnonew 3: where deptno = 40no rows selectedSQL>

Finally there's the anonymous PL/SQL block. As you see, we can still assign values to declared variables interactively:

SQL> set serveroutput on size unlimitedSQL> declare2 n pls_integer;3 l_sal number := 3500;4 l_dno number := &dno;5 begin6 select count(*)7 into n8 from emp9 where sal > l_sal10 and deptno = l_dno;11 dbms_output.put_line('top earners = '||to_char(n));12 end;13 /Enter value for dno: 10old 4: l_dno number := &dno;new 4: l_dno number := 10;top earners = 1PL/SQL procedure successfully completed.SQL>

Try using double quotes if it's a char variable:

DEFINE stupidvar = "'stupidvarcontent'";

or

DEFINE stupidvar = 'stupidvarcontent';SELECT stupiddata FROM stupidtable WHERE stupidcolumn = '&stupidvar'

upd:

SQL*Plus: Release 10.2.0.1.0 - Production on Wed Aug 25 17:13:26 2010Copyright (c) 1982, 2005, Oracle. All rights reserved.SQL> conn od/od@etalonConnected.SQL> define var = "'FL-208'";SQL> select code from product where code = &var;old 1: select code from product where code = &varnew 1: select code from product where code = 'FL-208'CODE---------------FL-208SQL> define var = 'FL-208';SQL> select code from product where code = &var;old 1: select code from product where code = &varnew 1: select code from product where code = FL-208select code from product where code = FL-208*ERROR at line 1:ORA-06553: PLS-221: 'FL' is not a procedure or is undefined

In PL/SQL v.10

keyword declare is used to declare variable

DECLARE stupidvar varchar(20);

to assign a value you can set it when you declare

DECLARE stupidvar varchar(20) := '12345678';

or to select something into that variable you use INTO statement, however you need to wrap statement in BEGIN and END, also you need to make sure that only single value is returned, and don't forget semicolons.

so the full statement would come out following:

DECLARE stupidvar varchar(20);BEGINSELECT stupid into stupidvar FROM stupiddata CC WHERE stupidid = 2;END;

Your variable is only usable within BEGIN and END so if you want to use more than one you will have to do multiple BEGIN END wrappings

DECLARE stupidvar varchar(20);BEGINSELECT stupid into stupidvar FROM stupiddata CC WHERE stupidid = 2;DECLARE evenmorestupidvar varchar(20);BEGINSELECT evenmorestupid into evenmorestupidvar FROM evenmorestupiddata CCC WHERE evenmorestupidid = 42;INSERT INTO newstupiddata (newstupidcolumn, newevenmorestupidstupidcolumn)SELECT stupidvar, evenmorestupidvar FROM dualEND;END;

Hope this saves you some time

If you want to declare date and then use it in SQL Developer. 

DEFINE PROPp_START_DT = TO_DATE('01-SEP-1999')SELECT * FROM proposal WHERE prop_start_dt = &PROPp_START_DT

The question is about to use a variable in a script means to me it will be used in SQL*Plus.

The problem is you missed the quotes and Oracle can not parse the value to number.

SQL> DEFINE num = 2018SQL> SELECT &num AS your_num FROM dual;old 1: SELECT &num AS your_num FROM dualnew 1: SELECT 2018 AS your_num FROM dualYOUR_NUM----------2018Elapsed: 00:00:00.01

This sample is works fine because of automatic type conversion (or whatever it is called).

If you check by typing DEFINE in SQL*Plus, it will shows that num variable is CHAR.

SQL>defineDEFINE NUM = "2018" (CHAR)

It is not a problem in this case, because Oracle can deal with parsing string to number if it would be a valid number.

When the string can not parse to number, than Oracle can not deal with it.

SQL> DEFINE num = 'Doh'SQL> SELECT &num AS your_num FROM dual;old 1: SELECT &num AS your_num FROM dualnew 1: SELECT Doh AS your_num FROM dualSELECT Doh AS your_num FROM dual*ERROR at line 1:ORA-00904: "DOH": invalid identifier

With a quote, so do not force Oracle to parse to number, will be fine:

17:31:00 SQL> SELECT '&num' AS your_num FROM dual;old 1: SELECT '&num' AS your_num FROM dualnew 1: SELECT 'Doh' AS your_num FROM dualYOU---Doh

So, to answer the original question, it should be do like this sample:

SQL> DEFINE stupidvar = 'X'SQL>SQL> SELECT 'print stupidvar:' || '&stupidvar'2 FROM dual3 WHERE dummy = '&stupidvar';old 1: SELECT 'print stupidvar:' || '&stupidvar'new 1: SELECT 'print stupidvar:' || 'X'old 3: WHERE dummy = '&stupidvar'new 3: WHERE dummy = 'X''PRINTSTUPIDVAR:'-----------------print stupidvar:XElapsed: 00:00:00.00

There is an other way to store variable in SQL*Plus by using Query Column Value.

The COL[UMN] has new_value option to store value from query by field name.

SQL> COLUMN stupid_column_name new_value stupid_var noprintSQL> SELECT dummy || '.log' AS stupid_column_name2 FROM dual;Elapsed: 00:00:00.00SQL> SPOOL &stupid_var.SQL> SELECT '&stupid_var' FROM DUAL;old 1: SELECT '&stupid_var' FROM DUALnew 1: SELECT 'X.log' FROM DUALX.LOG-----X.logElapsed: 00:00:00.00SQL>SPOOL OFF;

As you can see, X.log value was set into the stupid_var variable, so we can find a X.log file in the current directory has some log in it.

Just want to add Matas' answer.Maybe it's obvious, but I've searched for a long time to figure out that the variable is accessible only inside the BEGIN-END construction, so if you need to use it in some code later, you need to put this code inside the BEGIN-END block.

Note that these blocks can be nested:

DECLARE x NUMBER;BEGINSELECT PK INTO x FROM table1 WHERE col1 = 'test';DECLARE y NUMBER;BEGINSELECT PK INTO y FROM table2 WHERE col2 = x;INSERT INTO table2 (col1, col2)SELECT y,'text'FROM dualWHERE exists(SELECT * FROM table2);COMMIT;END;END;

In Toad I use this works:

declare num number;begin ---- use 'select into' works --select 123 into num from dual;---- also can use :=num := 123;dbms_output.Put_line(num);end;

Then the value will be print to DBMS Output Window.

Reference to here and here2.

Here's your answer:

DEFINE num := 1; -- The semi-colon is needed for default values.SELECT &num FROM dual;

You can use a with clause and move filter criteria from a where to a join.

It helps here: Oracle SQL alternative to using DEFINE.

withmytab as (select 'stupidvarcontent' as myvar from dual)SELECTstupiddataFROMstupidtable a inner joinmytab bona.stupidcolumn = b.myvarWHERE ...;

It works in Oracle 12R2.
It works for one SQL command only.
It is standard ANSI notation.
I'm using it in SQL Developer.

One possible approach, if you just need to specify a parameter once and replicate it in several places, is to do something like this:

SELECTstr_size /* my variable usage */, LPAD(TRUNC(DBMS_RANDOM.VALUE * POWER(10, str_size)), str_size, '0') randFROMdual /* or any other table, or mixed of joined tables */CROSS JOIN (SELECT 8 str_size FROM dual); /* my variable declaration */

This code generates a string of 8 random digits.

Notice that I create a kind of alias named str_size that holds the constant 8. It is cross-joined to be used more than once in the query.

Sometimes you need to use a macro variable without asking the user to enter a value. Most often this has to be done with optional script parameters. The following code is fully functional

column 1 noprint new_value 1select '' "1" from dual where 2!=2;select nvl('&&1', 'VAH') "1" from dual;column 1 cleardefine 1

Similar code was somehow found in the rdbms/sql directory.

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