Question

我有一项任务，要求我从pgAdminIII中的表中提取多行，将行数据操作为几个新的行类型（或者只是以某种方式生成数据）。

因为实际操作似乎很难使用基本的sql命令，所以我决定尝试制作postgresql存储过程（或函数）。到目前为止，我所得到的只是语法错误。

我的postgresql功能：

CREATE FUNCTION getAllPayments(double precision, double precision, timestamp) RETURNS text AS $$
DECLARE
credLim ALIAS FOR $1;
paid ALIAS FOR $2;
pdate ALIAS FOR $3;
totalpayments double precision;
numberofpayments integer;
availablecredit double precision;
BEGIN
IF payments.customernumber = orders.customernumber THEN
	numberofpayments := COUNT(pdate);
	totalpayments := SUM(paid);
	availablecredit := credLim + totalpayments - numberofpayments;
SELECT customers.customername, customers.customernumber, credLim, availablecredit, totalpayments, numberofpayments from customers, payments;
ELSE
Return "failed attempt";
END IF;

END;

调用它的python脚本：

get_data = "getAllPayments(customers.creditlimit, payments.amount, payments.paymentdate)"
seperator = "---------------------------------------------------------------------------------"

crsr2 = conn.cursor()
crsr2.execute(get_data)

print('Customer Number   Customer Name   Payments Made   Value of Orders   Credit Limit   Available Credit')
print(seperator)
for x in crsr2:
    neu = str(x)
    w = neu.replace(', ', ',     ')
    print(w)
print(seperator)

Answer 1

我看到了

错误：在＃34; $$
附近未接受美元引用的字符串

终止该字符串，并告诉dbms您正在使用哪种语言。

CREATE FUNCTION getAllPayments(double precision, double precision, timestamp) 
RETURNS text AS $$
DECLARE
    credLim ALIAS FOR $1;
    paid ALIAS FOR $2;
    pdate ALIAS FOR $3;
    totalpayments double precision;
    numberofpayments integer;
    availablecredit double precision;
BEGIN
    IF payments.customernumber = orders.customernumber THEN
        numberofpayments := COUNT(pdate);
        totalpayments := SUM(paid);
        availablecredit := credLim + totalpayments - numberofpayments;

        SELECT customers.customername, customers.customernumber, credLim, availablecredit, totalpayments, numberofpayments from customers, payments;

    ELSE
        Return "failed attempt";
    END IF;
END;
$$                   -- Terminate the string.
language plpgsql;    -- Identify the language.

那应该让它编译。我没有试着看它是否有意义，但我注意到了这条线

        availablecredit := credLim + totalpayments - numberofpayments;

看起来有点可疑，不使用ANSI连接通常是个坏主意。

如何创建可以使用python脚本调用的postgresql函数？

1 个答案: