运算符

AND OR NOT

{
SELECT *
FROM customers
WHERE NOT (birth_date >'1990-01-01' OR points>1000 );
}

IN

{
SELECT *
FROM products
WHERE quantity_in_stock IN (49,38,72) -- quantity=49 OR 38 OR 72
}

BETWEEN

{
SELECT *
FROM customers
WHERE birth_date BETWEEN '1990-01-01' AND '2000-01-01'
}

LIKE

{
SELECT *
FROM customers
WHERE last_name LIKE '%b%'  -- % represent any number of characters

---

SELECT *
FROM customers
WHERE last_name NOT LIKE 'b____y'  --  _ represent single characters

---

SELECT *
FROM customers
WHERE address LIKE '%trail%' OR 
	   address LIKE '%avenue%'
}

REGEXP(正则表达式)

{
SELECT *
FROM customers
WHERE last_name REGEXP 'field$|^mac|rose' -- ^ beginning  $ end | logical OR

---

SELECT *
FROM customers
WHERE last_name REGEXP 'e[gim]'  -- 等价于eg OR ei OR em

---

SELECT *
FROM customers
WHERE last_name REGEXP '[a-h]e' -- from a to h和e组合,等价于ae OR be OR ce …OR he
}

IS NULL

{
SELECT *
FROM customers
WHERE phone IS NOT NULL
}

ORDER BY

{
SELECT *
FROM customers
ORDER BY state DESC,first_name -- DESC 降序

---

SELECT first_name,last_name
FROM customers
ORDER BY birth_date

---

SELECT first_name,last_name,points
FROM customers
ORDER BY 1,2 -- 表示用相对列顺序排序,对应SELECT的顺序,这里等价于ORDER BY first_name,last_name

---

SELECT 
  *,
  quantity*unit_price AS total_price
FROM order_items
WHERE order_id=2
ORDER BY total_price DESC
}

LIMIT

{
SELECT *
FROM customers
LIMIT 6,3  --  其中6是偏移量,表示跳过前6条记录(行),从第7行开始(包括第7行)获取3条记录,这里每个记录即为 一行

---

SELECT *
FROM customers
ORDER BY points DESC
LIMIT 3 -- 等价于LIMIT 0,3 ,是直接取值到第3位
}
posted @   ganwong99  阅读(4)  评论(0编辑  收藏  举报
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