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Sometimes you need to fix a production defect. To do it, you need to mirror a specific set of data, and do a test to proof the bug and then fix it.
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For a complete description see https://www.codeproject.com/Articles/33052/Visual-Representation-of-SQL-Joins
All the Join you want -
The Sqlite Oracle Compatibility Functions is an experimental compatibility layer for SQLite vs Oracle, written in Python 3.
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Sometimes you need to remove nasty duplicate on a table, based on a subset of the column. On every big database there is something called “rowid” which can be used to indentify a column in a unique way. On PostgreSQL is called ctid, as we shall see:
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[caption id=“attachment_5294” align=“alignright” width=“150”]
Disapprove with me![/caption]
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I stumbled upon a very brain-f**k error on Oracle 10g on these days.
Context: the following query [sql]SELECT * FROM (
SELECT TO_NUMBER(CUSTOMER_ID) AS SNDG FROM BAD_CODES_TABLE WHERE
AND I_LIKE=UPPER(‘STATIC_CONDITION’) AND CUSTOMER_ID NOT LIKE ‘%P%’ ) S WHERE TO_NUMBER(S.SNDG) >2000[/sql] could trigger a Invalid number if CUSTOMER_ID column contains invalid numbers.Why?
Well鈥f you ask to “explain plan”, you will get something like
- a table full scan
- Filter Predicates AND
- I_LIKE=UPPER('STATIC_CONDITION')
- TO_NUMBER(S.SNDG) >2000
- CUSTOMER_ID NOT LIKE '%P%'
- Filter Predicates AND
Read More - a table full scan
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聽Come evitare iniezione SQL: lato SQL Server (SP_EXECUTESQL)
In generale va evitato nel modo pi霉 assoluto la scrittura di query sql diamiche.Va evitato cio猫 聽l鈥檜so lato SQL Server di sp_executesql e EXEC
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