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  • 0116-06-侯舒舒(作业-sql)

    2020 01 16

    • 选择数据库
      • use test
    • 返回数据库列表
      • show DATABASES
    • 获取数据库表的列表
      • show TABLES
    • 显示表列
      • show COLUMNS FROM customers
    • 检索单个列
      • SELECT prod_name
        FROM products
    • 检索多个列
      • SELECT prod_name,prod_id,prod_price
        FROM products
    • 检查所有列
      • SELECT *
        FROM products
    • 检索值
      • SELECT vend_id
        FROM products
    • 检索值 只返回不用的值 DISTINCT关键字
      • SELECT DISTINCT vend_id
        FROM products
    • 检索列限制结果LIMIT 5不多于5行
      • SELECT prod_name
        FROM products
        LIMIT 5
    • 而LIMIT 5,5指的是返回从行5开始的5行,第一个数为开始位置,第二个数为要检索的行数。
      • SELECT prod_name
        FROM products
        LIMIT 5,5
    • 完全限定表名,同时制定表名和列字
      • SELECT products.prod_name
        FROM products
    • 排序数据
      • SELECT prod_name
        FROM products
        ORDER BY prod_name
    • 按多列排序
      • SELECT prod_id,prod_price,prod_name
        FROM products
        ORDER BY prod_price,prod_name
    • 指定排序方向
      • SELECT prod_id,prod_price,prod_name
        FROM products
        ORDER BY prod_price DESC
    • 使用组合找到最贵的
      • SELECT prod_price
        FROM products
        ORDER BY prod_price DESC
        LIMIT 1
    • 过滤语句WHERE
      • SELECT prod_name,prod_price
        FROM products
        WHERE prod_price=2.50
    • 检查单个值
      • SELECT prod_name,prod_price
        FROM products
        WHERE prod_name='fuses'
    • 不匹配检查
      • SELECT vend_id,prod_name
        FROM products
        WHERE vend_id <> 1003
    • 范围值检查 关键字BETWEEN
      • SELECT prod_name,prod_price
        FROM products
        WHERE prod_price BETWEEN 5 AND 10
    • 空值检查
      • SELECT prod_name
        FROM products
        WHERE prod_price IS NULL
    • and操作符
      • SELECT prod_id,prod_price,prod_name
        ROM products
        WHERE vend_id=1003 AND prod_price<=10
    • or操作符
      • SELECT prod_name,prod_price
        FROM products
        WHERE vend_id = 1002 OR vend_id=1003
    • 计算次序,在计算or前 优先计算and
      • SELECT prod_name,prod_price
        FROM products
        WHERE vend_id = 1002 OR vend_id=1003 AND prod_price>=10
    • in操作符
      • SELECT prod_name,prod_price
        FROM products
        WHERE vend_id IN (1002,1003)
        ORDER BY prod_name
    • not操作符
      • SELECT prod_name,prod_price
        FROM products
        WHERE vend_id NOT IN (1002,1003)
        ORDER BY prod_name
    • 百分号通配符 使用通配符 必须使用LIKE
      • SELECT prod_id,prod_name
        FROM products
        WHERE prod_name LIKE 'jet%'
    • 下划线通配符
      • SELECT prod_id,prod_name
        FROM products
        WHERE prod_name LIKE '_ ton anvil'
    • 基本字符匹配 REGEXP后跟的作为正则表达式
      • SELECT prod_name
        FROM products
        WHERE prod_name REGEXP '1000'
        ORDER BY prod_name
    • 进行or匹配
      • SELECT prod_name
        FROM products
        WHERE prod_name REGEXP '1000|2000'
        ORDER BY prod_name
    • 匹配几个字符之一
      • SELECT prod_name
        FROM products
        WHERE prod_name REGEXP '[123] Ton'
        ORDER BY prod_name
    • 匹配范围
      • SELECT prod_name
        FROM products
        WHERE prod_name REGEXP '[1-5] Ton'
        ORDER BY prod_name
    • 匹配特殊字符
      • SELECT vend_name
        FROM vendors
        WHERE vend_name REGEXP '.'
        ORDER BY vend_name
    • 匹配多个实列
      • SELECT prod_name
        FROM products
        WHERE prod_name REGEXP '([0-9] sticks?)'
        ORDER BY prod_name
    • 定位符^
      • SELECT prod_name
        FROM products
        WHERE prod_name REGEXP '^([0-9.])'
        ORDER BY prod_name
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  • 原文地址:https://www.cnblogs.com/demohou/p/12203852.html
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