PL/SQL Statement ignored : missing expression

Question

I have a little DB with 3 tables: account, account_statements and account operations. I need to know:

1. all credit operations of the period

2. all debet operations of the perion

3. a balance on any date

My script is:

    CREATE TABLE account 
(
   id number(10) NOT NULL,
   account number(20) NOT NULL,
   CONSTRAINT account_id PRIMARY KEY (id)
);


CREATE TABLE account_statements
(
   id number(10) NOT NULL,
   account_id number(10) NOT NULL,
   statement_date date,
   inbalance number(20,2),
   outbalance number (20,2),
   CONSTRAINT statement_id PRIMARY KEY (id),
   CONSTRAINT account_statements_foreign_id FOREIGN KEY (account_id) REFERENCES account(id)
);


CREATE TABLE account_operations
(
   id number(10) NOT NULL,
   account_id number(10) NOT NULL,
   operdate date,
   summ number(20,2),
   opertype char(6),
   CONSTRAINT operations_id PRIMARY KEY (id),
   CONSTRAINT account_operations_foreign_id FOREIGN KEY (account_id) REFERENCES account(id)
);

CREATE OR REPLACE FUNCTION Get_debet_on_period (
   v_startdate IN date,
   v_enddate IN date,
   v_account IN account.account%TYPE)
RETURN number
IS
   v_debet_summ number(20,2);
BEGIN
   SELECT SUM(summ) INTO v_debet_summ
   FROM account_operations ao,
      account a
   WHERE ao.operdate between v_startdate AND v_enddate
      AND ao.opertype='DEBET'
      AND a.account=v_account
      AND ao.account_id=a.id;

    RETURN v_debet_summ;
END;

CREATE OR REPLACE FUNCTION Get_credit_on_period (
   v_startdate IN date,
   v_enddate IN date,
   v_account IN account.account%TYPE)
RETURN number
IS
   v_credit_summ number(20,2);
BEGIN
   SELECT SUM(summ) INTO v_credit_summ
   FROM account_operations ao,
      account a
   WHERE ao.operdate between v_startdate AND v_enddate
      AND ao.opertype='CREDIT'
      AND a.account=v_account
      AND ao.account_id=a.id;
    RETURN v_credit_summ;
END;

CREATE OR REPLACE FUNCTION Get_balance_on_date (
   v_date IN date,
   v_account IN account.account%TYPE)
RETURN number
IS 
   v_balance_summ number(20,2);
   v_startdate date; 
   v_startsumm number;
BEGIN
   SELECT MAX(as.statement_date) INTO v_startdate
   FROM account_statements as, account a
   WHERE a.id=as.account_id
   AND a.account=v_account
   AND as.statement_date<v_date;
   IF v_startdate IS NOT NULL THEN
      SELECT as.outbalance INTO v_startsumm
      FROM account_statement as, account a
      WHERE a.id=as.account_id
      AND a.account=v_account
      AND as.statement_date=v_statement_date;
      v_balance_summ:=v_startsumm+Get_credit_on_period(v_startdate, v_date, v_account)-Get_debet_on_period(v_startdate, v_date, v_account);
    ELSE
      v_startsumm:=0;
      v_balance_summ:=Get_credit_on_period(v_startdate, v_date, v_account)-Get_debet_on_period(v_startdate, v_date, v_account);
    END IF;

   RETURN v_balance_summ;
END;

I have an error in function Get_balance_on_date:

Errors: FUNCTION GET_BALANCE_ON_DATE Line/Col: 10/4 PL/SQL: SQL Statement ignored Line/Col: 10/15 PL/SQL: ORA-00936: missing expression Line/Col: 16/7 PL/SQL: SQL Statement ignored Line/Col: 16/14 PL/SQL: ORA-00936: missing expression

Answer 1

Your function get_balance_on_date does not compile.

1. You're using table account_statement, however you created table named in plural form account_statements.
2. You're using reserved keyword AS as an alias "account_statements as". You should change the alias to something different.
3. You're using undeclared variable "v_statement_date".

Fixed function for you:

CREATE OR REPLACE FUNCTION get_balance_on_date
(
    v_date    IN DATE
   ,v_account IN account.account%TYPE
) RETURN NUMBER IS
    v_balance_summ NUMBER(20, 2);
    v_startdate    DATE;
    v_startsumm    NUMBER;
    v_statement_date DATE; -- Remove this if you don't need, created this for function to compile
BEGIN
    SELECT MAX(stm.statement_date)
      INTO v_startdate
      FROM account_statements stm
          ,account            a
     WHERE a.id = stm.account_id
       AND a.account = v_account
       AND stm.statement_date < v_date;

    IF v_startdate IS NOT NULL
    THEN
        SELECT stm.outbalance
          INTO v_startsumm
          FROM account_statements stm
              ,account           a
         WHERE a.id = stm.account_id
           AND a.account = v_account
           AND stm.statement_date = v_statement_date;

        v_balance_summ := v_startsumm +
                          get_credit_on_period(v_startdate, v_date, v_account) -
                          get_debet_on_period(v_startdate, v_date, v_account);
    ELSE
        v_balance_summ := get_credit_on_period(v_startdate, v_date, v_account) -
                          get_debet_on_period(v_startdate, v_date, v_account);
    END IF;

    RETURN v_balance_summ;
END;

Answer 2

You are using a reserved keyword as an alias

FROM account_statements as, account a

as has to be changed to something else since it is part of the SQL language.