Power Selecting - As (Page 4 of 6 ) Sometimes a column name returned in a query is different from what is expected or what might be needed for a script. As a simple example, consider a query that uses the MySQL function COUNT to return the number of records in a table: SELECT COUNT(*) FROM Clients;
COUNT(*)
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12 |
While COUNT(*) might be a suitable column header for raw output, it wouldn't be so nice to work with as the key of an associative array. Instead, The AS modifier can be used to rename a results column. SELECT COUNT(*) AS RecordCount FROM Clients;
RecordCount
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12 |
AS only affects the column name of the returned results; it does not actually rename a table column stored within the database, but it can still be a powerful ally when writing complex SELECT queries. Consider the next example which uses the MySQL function CONCAT to combine column data. SELECT CONCAT(LastName, ", ", FirstName) AS Name, CONCAT(Address,
" ", CITY, ", ", State, " ", Zip) as Address FROM Clients ORDER BY
Name ASC;
Name Address
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Adams, Joseph 214 Main St Seattle, WA 98102
Adams, Gwendolyn 205 W Third St Brownville, AL 35020
Brown, Michael 2336 NE Cranston Blvd Terre Haute, IN 47814
Chavez, Jose 14 Quailbush Dr Jasper, TN 37347
Copland, Dorothy 639 Spring St West Sacramento CA, 95691
Franklin, Susanna 293 Lamont Dr Tempe, AZ 85283
Johnson, Diane 82 Richardson Ave Fresno, CA 93702
LaBelle, Nathan 367 Pineview Ter Skaneateles, NY 13152
Smith, Aaron 9112 Main St San Diego, CA 92119
Smith, Harold 321 Elm St Portsmouth, RI 02871
Smith, Josh 52 Harding Ln Franklin, MA 02038
Wilson, Jessica 227 Washington Ave Irving, TX 75061 |
AS coerces the name of a column to something manageable or in some cases, intelligible. The column names would be quite messy indeed without AS! Next: Like >>
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