postgresql is null
Do not write expression = NULL because NULL is not "equal to" NULL. (The null value represents an unknown value, and it is not known whether two unknown ... ,Ordinary comparison operators yield null (signifying "unknown"), not true or false, when either input is null. For example, 7 = NULL yields null, as does 7 ...
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 postgresql is null 相關參考資料
PostgreSQL: Documentation: 9.1: Comparison Operators
Ordinary comparison operators yield null (signifying "unknown"), not true or false, when either input is null. For example, 7 = NULL yields null, as does 7 ... https://www.postgresql.org PostgreSQL: Documentation: 8.1: Comparison Operators
Do not write expression = NULL because NULL is not "equal to" NULL. (The null value represents an unknown value, and it is not known whether two unknown ... https://www.postgresql.org PostgreSQL: Documentation: 9.4: Comparison Operators
Ordinary comparison operators yield null (signifying "unknown"), not true or false, when either input is null. For example, 7 = NULL yields null, as does 7 ... https://www.postgresql.org PostgreSQL: Documentation: 9.6: Comparison Functions and Operators
a NOT BETWEEN SYMMETRIC x AND y, not between, after sorting the comparison values. a IS DISTINCT FROM b, not equal, treating null like an ordinary value. https://www.postgresql.org PostgreSQL: IS NULL Condition - TechOnTheNet
This PostgreSQL tutorial explains how to use the PostgreSQL IS NULL condition with syntax and examples. The PostgreSQL IS NULL condition is used to test ... https://www.techonthenet.com PostgreSQL: IS NOT NULL - TechOnTheNet
Here is an example of how to use the PostgreSQL IS NOT NULL condition in a SELECT statement: SELECT * FROM employees WHERE first_name IS NOT NULL; This PostgreSQL IS NOT NULL example will return all r... https://www.techonthenet.com PostgreSQL NULL值- PostgreSQL基礎教程 - 極客書
PostgreSQL的NULL 是一個術語，用來代表一個缺失值。 NULL值表中的一個字段中的值，顯示為空白。 一個NULL值的字段與字段冇有值。這是非常重要的，要了解的 ... http://tw.gitbook.net sql server - What is the PostgreSQL equivalent for ISNULL ...
SELECT CASE WHEN field IS NULL THEN 'Empty' ELSE field END AS field_alias ... Coalesce will return the first non null value in the list. Thus ... https://stackoverflow.com PostgreSQL - NULL Values - Tutorialspoint
https://www.tutorialspoint.com PostgreSQL: Documentation: 8.3: Comparison Operators
Do not write expression = NULL because NULL is not "equal to" NULL. (The null value represents an unknown value, and it is not known whether two unknown values are equal.) This behavior conf... https://www.postgresql.org |