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我在mysql表中有以下数据：

Spring Texas
Corpus Christi Texas
Orange California
Los Angeles California

数据的右边永远是州名。我想运行一个仅显示加利福尼亚城市的 sql 查询，并将 $city 设置为返回字符串的城市名称部分的数组。有些城市有空间，如洛杉矶，有些则没有。

实现此目的的最佳方法是什么，以确保我只获得加利福尼亚城市，并且只有分配给 $city 的城市部分

像这样的东西，但从 sql 的角度来看，这是最好的方法吗？

Select
   terms.name
From
  terms
Where
  terms.name Like '%Texas%'
4

1 回答 1

1

尝试标准化数据。

如果不能，请设置一个带有州名的表格。

SELECT c.col,
  TRIM(SUBSTR(c.col, 1, LENGTH(c.col) - LENGTH(c.state))) AS city,
  c.state AS state
FROM (SELECT a.col,
    CASE
      WHEN b.state IS NULL
        THEN SUBSTRING_INDEX(a.state, ' ', -1)
      ELSE b.state
    END AS state
  FROM
    (SELECT col,
      CASE
        WHEN LENGTH(col) - LENGTH(REPLACE(col, ' ', '')) + 1 = 2
          THEN SUBSTRING_INDEX(col, ' ', -1)
        WHEN LENGTH(col) - LENGTH(REPLACE(col, ' ', '')) + 1 > 2
          THEN SUBSTRING_INDEX(col, ' ', -2)
        ELSE NULL
      END AS state
    FROM bad_data) a
  LEFT JOIN state_names b ON b.state = a.state) c

结果

| 色彩 | 城市 | 状态 |
-------------------------------------------------- ----
| 德克萨斯州春季 | 弹簧 | 德州 |
| 德克萨斯州科珀斯克里斯蒂 | 科珀斯克里斯蒂 | 德州 |
| 橙色加利福尼亚 | 橙色 | 加利福尼亚 |
| 纽约纽约 | 纽约 | 纽约 |

查看演示

如果你不能建立一个表，那么这个查询应该这样做：

SELECT c.col,
  TRIM(SUBSTR(c.col, 1, LENGTH(c.col) - LENGTH(c.state))) AS city,
  c.state AS state
FROM (SELECT a.col,
    CASE
      WHEN b.state IS NULL
        THEN SUBSTRING_INDEX(a.state, ' ', -1)
      ELSE b.state
    END AS state
  FROM
    (SELECT col,
      CASE
        WHEN LENGTH(col) - LENGTH(REPLACE(col, ' ', '')) + 1 = 2
          THEN SUBSTRING_INDEX(col, ' ', -1)
        WHEN LENGTH(col) - LENGTH(REPLACE(col, ' ', '')) + 1 > 2
          THEN SUBSTRING_INDEX(col, ' ', -2)
        ELSE NULL
      END AS state
    FROM bad_data) a
  LEFT JOIN (SELECT 'Alabama' AS state 
                  UNION ALL 
                  SELECT 'Arizona' 
                  UNION ALL 
                  SELECT 'Arkansas' 
                  UNION ALL 
                  SELECT 'California' 
                  UNION ALL 
                  SELECT 'Colorado' 
                  UNION ALL 
                  SELECT 'Connecticut' 
                  UNION ALL 
                  SELECT 'Delaware' 
                  UNION ALL 
                  SELECT 'Florida' 
                  UNION ALL 
                  SELECT 'Georgia' 
                  UNION ALL 
                  SELECT 'Guam' 
                  UNION ALL 
                  SELECT 'Hawaii' 
                  UNION ALL 
                  SELECT 'Idaho' 
                  UNION ALL 
                  SELECT 'Illinois' 
                  UNION ALL 
                  SELECT 'Indiana' 
                  UNION ALL 
                  SELECT 'Iowa' 
                  UNION ALL 
                  SELECT 'Kansas' 
                  UNION ALL 
                  SELECT 'Kentucky' 
                  UNION ALL 
                  SELECT 'Louisiana' 
                  UNION ALL 
                  SELECT 'Maine' 
                  UNION ALL 
                  SELECT 'Maryland' 
                  UNION ALL 
                  SELECT 'Massachusetts' 
                  UNION ALL 
                  SELECT 'Michigan' 
                  UNION ALL 
                  SELECT 'Minnesota' 
                  UNION ALL 
                  SELECT 'Mississippi' 
                  UNION ALL 
                  SELECT 'Missouri' 
                  UNION ALL 
                  SELECT 'Montana' 
                  UNION ALL 
                  SELECT 'Nebraska' 
                  UNION ALL 
                  SELECT 'Nevada' 
                  UNION ALL 
                  SELECT 'New Hampshire' 
                  UNION ALL 
                  SELECT 'New Jersey' 
                  UNION ALL 
                  SELECT 'New Mexico' 
                  UNION ALL 
                  SELECT 'New York' 
                  UNION ALL 
                  SELECT 'North Carolina' 
                  UNION ALL 
                  SELECT 'North Dakota' 
                  UNION ALL 
                  SELECT 'Ohio' 
                  UNION ALL 
                  SELECT 'Oklahoma' 
                  UNION ALL 
                  SELECT 'Oregon' 
                  UNION ALL 
                  SELECT 'Pennsylvania' 
                  UNION ALL 
                  SELECT 'Puerto Rico' 
                  UNION ALL 
                  SELECT 'Rhode Island' 
                  UNION ALL 
                  SELECT 'South Carolina' 
                  UNION ALL 
                  SELECT 'South Dakota' 
                  UNION ALL 
                  SELECT 'Tennessee' 
                  UNION ALL 
                  SELECT 'Texas' 
                  UNION ALL 
                  SELECT 'Utah' 
                  UNION ALL 
                  SELECT 'Vermont' 
                  UNION ALL 
                  SELECT 'Virginia' 
                  UNION ALL 
                  SELECT 'Washington' 
                  UNION ALL 
                  SELECT 'West Virginia' 
                  UNION ALL 
                  SELECT 'Wisconsin' 
                  UNION ALL 
                  SELECT 'Wyoming') b ON b.state = a.state) c
于 2013-01-16T00:24:42.030 回答