Question

I have the following data in mysql table:

Spring Texas
Corpus Christi Texas
Orange California
Los Angeles California

The right of the data will always be the state name. I want to run a sql query that shows only cities in California, and sets $city to an array of the city name portion of the returned string. Some cities have spaces such as los angeles and some don’t.

What is the best method to accomplish this to ensure I only get California cities, and only the city portion assigned to $city

Something like this, but is this the best way from an sql standpoint?

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

Answer 1

Try to normalize the data.

If you can’t, set up a table with state names.

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

Result

|                  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

If you can’t set up a table, then this query should do it:

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