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Question about joining tables
comp.databases.theory comp.databases.theory
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#1
 
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Question about joining tables -
02-22-2008
, 05:26 PM
#2
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#3
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#4
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#5
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#6
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#7
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#8
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#9
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
#10
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Hi, Say I have two tables, one called property which stores details of properties, and anothe called property_image that stores a single image for a property. So either property may have one image or no image. I know how to do the following join: SELECT * FROM property, property_image WHERE property.property_id = property_image.property_id Works fine if I need only returned the properties that tie up with images but the properties that dont tie up I dont get returned in my result. Is it possible to create an SQL joining statement where all properties would be returned including the ones that dont have an property image? Those that dont just wouldnt have any values in the property_image.* columns. Traditionally I would do a query on the property table then for each property do a single SELECT lookup on the property_image table .. im sure for performance if i could reduce this to one query i would see an improvement. Thanks Burnsy |
unions but more people know outer joins than know unions for some reason.)
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