Difference between revisions of "String over columns"
| Line 6: | Line 6: | ||
name VARCHAR(20), | name VARCHAR(20), | ||
floorcolor VARCHAR(20), | floorcolor VARCHAR(20), | ||
| − | ceilingcolor | + | ceilingcolor VARCHAR(20), |
| − | wallcolor VARCHAR(20); | + | wallcolor VARCHAR(20)); |
INSERT INTO bedrooms VALUES ('Jim','RED','GREEN','YELLOW'); | INSERT INTO bedrooms VALUES ('Jim','RED','GREEN','YELLOW'); | ||
INSERT INTO bedrooms VALUES ('Bob','YELLOW','BLUE','BLACK'); | INSERT INTO bedrooms VALUES ('Bob','YELLOW','BLUE','BLACK'); | ||
Revision as of 10:56, 30 July 2012
Search for a string across columns
DROP TABLE bedrooms
CREATE TABLE bedrooms( name VARCHAR(20), floorcolor VARCHAR(20), ceilingcolor VARCHAR(20), wallcolor VARCHAR(20)); INSERT INTO bedrooms VALUES ('Jim','RED','GREEN','YELLOW'); INSERT INTO bedrooms VALUES ('Bob','YELLOW','BLUE','BLACK'); INSERT INTO bedrooms VALUES ('Allan','BLUE','PINK','BLACK'); INSERT INTO bedrooms VALUES ('George','BLUE','GREEN','OAK');
SELECT name FROM bedrooms WHERE floorcolor = 'YELLOW' OR ceilingcolor = 'YELLOW' OR wallcolor = 'YELLOW'
Using OR increases the chances for careless mistakes instead CONCAT could be used to make the query more efficient. To avoid problems make sure to add in separators and if a value cna be null make sure to use it is wrapped in COALESCE OR NVL for example: COALESCE(floorcolor,).
SELECT name FROM bedrooms WHERE CONCAT (':',floorcolor,':',ceilingcolor,':',wallcolor,':') LIKE '%:YELLOW:%'
Hack 10 Converting subqueries into joins
Hack 11 Converting aggregate subqueries into joins
Hack 16 Search for a String across columns
Hack 24 Multiply Across a Result Set
Hack 25.5 Splitting and combining columns
Hack 26 Include the rows your JOIN forgot
Hack 30 Calculate the maximum/minimum of two fields
Hack 33 Get values and subtotals in one shot
Hack 50 Combine tables containing different data
Hack 51/52 Display rows as columns
Hack 55 Import Someone Else's Data
Hack 62 Issue Queries Without Using a Table
Hack 63 Generate rows without tables
Hack 72 Extract a subset of the results
Hack 78 Break it down by Range
Hack 88 Test two values from a subquery
