一、sqlwhen函數
1、sqlwhen函數用法:根據表達式的值進行一項或多項操作,其基本語法如下:
SELECT
...
,
CASE value_expression
WHEN when_expression THEN result_expression [ ...n ]
[ ELSE else_expression ]
END
...
2、sqlwhen函數實例:
SELECT
P.ProductID,
P.Name,
P.ListPrice,
CASE P.Color
WHEN 'Red' THEN 'R'
WHEN 'Silver' THEN 'S'
ELSE 'N/A'
END AS ColorGroup
FROM
Production.Product P;
二、sql中mod函數的使用方法
1、sql中mod函數的用法:計算兩個表達式的除數和被除數之間的餘數,基本語法如下:
SELECT MOD (number,divisor) FROM table_name;
-- 或者
SELECT number MOD divisor FROM table_name;
2、sql中mod函數實例:
SELECT
MOD(count(*),4) as result
FROM
Orders;
-- 結果為 1
三、sqlsum函數
1、sqlsum函數用法:求和函數,它將返回數值列的總和,基本語法如下:
SELECT SUM(column_name) FROM table_name;
2、sqlsum函數實例:
SELECT
SUM(TotalDue) as 'Total Sales'
FROM
Sales.SalesOrderHeader;
四、sql函數in
1、sql函數in用法:判斷某個欄位的值是否在給定的值列表中,基本語法如下:
SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1, value2, ...);
2、sql函數in實例:
SELECT
CustomerID,
OrderDate
FROM
Sales.SalesOrderHeader
WHERE
CustomerID IN (10051,10063,10073);
五、sqlover函數
1、sqlover函數用法:返回某個條件的結果為true時,對應的返回值;否則,返回另一個表達式的結果,基本語法如下:
SELECT
...
, IIF ( boolean_expression, true_value, false_value )
FROM
...;
2、sqlover函數實例:
SELECT
AVG(IIF(salary > 10000, salary, salary*1.1))
FROM
employees;
六、sql函數大全
1、sql函數大全實例:
SELECT
product_name,
CONCAT(category, " ", product_name) as full_name,
IF(price >= 50, "Expensive", "Cheap") as price_level,
UPPER(product_name) as upper_name,
CHAR_LENGTH(product_name) as name_length
FROM
products;
七、sqlite函數大全
1、sqlite函數大全實例:
SELECT
LENGTH("Hello World") as string_length,
SUBSTR("Hello World", 1, 5) as first_five_chars,
UPPER("Hello World") as upper_case,
LOWER("Hello World") as lower_case,
TRIM(" Hello ") as trimmed_string
FROM
tablename;
八、sql函數
1、sql函數用法:函數是SQL語句中的特殊指令,用於完成特定的操作。SQL定義了很多內置函數,此外還支持自定義函數,基本語法如下:
SELECT function_name(parameters) FROM tablename;
2、sql函數實例:
SELECT
LEFT('Techonthenet.com', 6) as site_name,
RIGHT('Techonthenet.com', 3) as domain_name;
九、函數sqlserver
1、函數sqlserver實例:
SELECT
DATENAME(month, GETDATE()) as Month,
DATENAME(year, GETDATE()) as Year,
DATEPART(year, GETDATE()) as Yr;
十、accesssql函數
1、accesssql函數實例:
SELECT
UCASE(Name) as NameUC,
LCASE(Name) as NameLC,
Len(Name) as NameLength,
InStr(Name, 'G') as G_Char_Index
FROM
Customers;
十一、sqlmod函數
1、sqlmod函數用法:計算兩個表達式的除數和被除數之間的餘數,基本語法如下:
SELECT MOD (number,divisor) FROM table_name;
-- 或者
SELECT number MOD divisor FROM table_name;
2、sqlmod函數實例:
SELECT
MOD(count(*),4) as result
FROM
Orders;
-- 結果為 1
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