update queries.

[sepoto]

I have developed the following queries but they do not operate. I get no errors from PHP or if I run them in MySQL WorkBench or PHPmyadmin. The queries do nothing at all which is the problem. The queries are supposed to set mz to 1 for the correct records. It is not working and I do not know why. I also verified that there are records that exist with lng and lat specified and import date specified. They are there for certain.

UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.291' AND lat='34.0618' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.351' AND lat='34.0622' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.344' AND lat='34.0871' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.331' AND lat='34.0402' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.286' AND lat='34.0235' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.278' AND lat='34.0453' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.46' AND lat='33.9709' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.469' AND lat='33.9821' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.439' AND lat='33.9861' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.474' AND lat='33.9959' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.473' AND lat='33.9921' LIMIT 1'UPDATE planning SET mz='1' WHERE import_date='5/10/2011 12:00:00 AM' AND lng='-118.467' AND lat='33.9911' LIMIT 1'

[justsomeguy]

There's an extra quote at the end, which would generate an error.

[sepoto]

UPDATE planning SET mz=1 WHERE import_date='5/4/2011 12:00:00 AM' AND lng LIKE -118.413 AND lat LIKE 34.0593UPDATE planning SET mz=1 WHERE import_date='5/4/2011 12:00:00 AM' AND lng LIKE -118.285 AND lat LIKE 34.0215UPDATE planning SET mz=1 WHERE import_date='5/4/2011 12:00:00 AM' AND lng LIKE -118.316 AND lat LIKE 34.0482UPDATE planning SET mz=1 WHERE import_date='5/4/2011 12:00:00 AM' AND lng LIKE -118.469 AND lat LIKE 33.9948

I managed to get it working but there is one thing I do not understand. To begin with lng and lat are floats. I am forced to use LIKE for some reason instead of "=". If I use "=" in place of LIKE nothing updates. If I look at the values of lat & lng they are exactly as the query appears. No extra numbers or numbers left out. This does not make sense at all.

[jeffman]

Floats are not stored the way you probably think they are. (For example, 4.5 might be represented as something like 4.499999999; check the warning here.) If you need an EXACT representation of a float to a limited number of decimals, it might be better to store it as a string type. OTOH, if there is no chance that this level of imprecision will create collisions, using LIKE might be good enough

[justsomeguy]

Unless you're actually doing math with them, you might as well store them as regular strings even.