Question

我在mysql表中有以下数据：

Spring Texas
Corpus Christi Texas
Orange California
Los Angeles California

数据的权利始终是州名。我想运行一个只显示加利福尼亚州城市的SQL查询，并将$ city设置为返回字符串的城市名称部分的数组。有些城市有洛杉矶等空间，有些则没有。

实现这一目标的最佳方法是什么，以确保我只获得加利福尼亚州的城市，只有城市部分分配给$ city

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%'

Answer 1

尝试规范化数据。

如果不能，请设置一个包含州名的表。

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

<强>结果

|                  COL |           CITY |      STATE |
------------------------------------------------------
|         Spring Texas |         Spring |      Texas |
| Corpus Christi Texas | Corpus Christi |      Texas |
|    Orange California |         Orange | California |
|    New York New York |       New York |   New York |

See the demo

如果您无法设置表格，则此查询应该执行此操作：

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

MySql查询特定状态并从返回的结果中分离城市

1 个答案:

See the demo