SQL Insert into table only if record doesn't exist
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Check if a row exists, otherwise insert
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Insert if not exists, else return id in postgresql
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Custom unique constraint, only enforced if one column has a specific value
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PDO mysql: How to know if insert was successful
132527
Unique constraint that allows empty values in MySQL
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Find records from one table which don't exist in another
110522
Insert, on duplicate update in PostgreSQL?
133977
Alter CONSTRAINT or stored procedure only to check when insert not on update
14137
Why isn't my SQL query to insert a table row working properly?
79118
How to avoid multiple insert in PostgreSQL
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Check if table exists
11016
Android SQL - Check if whole row already exists in database
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IF EXISTS taking longer than embedded select statement
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Insert into select and update in single query
10221
Sql insert query performance
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How do I check in SQLite whether a table exists?
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Can a foreign key be NULL and/or duplicate?