1在SQL中是否总是等于1？

1在SQL中是否总是等于1？

SELECT 1='1'

给人

TRUE

因为

'1'

是一个正确的构造函数

INT

中知道我所有的实现。

但是SQL使用严格的类型，请注意：

# SELECT 1=CAST('1' AS TEXT);ERROR:  operator does not exist: integer = textLINE 1: SELECT 1=CAST('1' AS TEXT);     ^HINT:  No operator matches the given name and argument type(s). You might need to add  explicit type casts.

关于标准（SQL 92、99和2003），这似乎是错误的：

     <literal> ::= <signed numeric literal>          | <general literal>     <general literal> ::= <character string literal>          | <national character string literal>          | <bit string literal>          | <hex string literal>          | <datetime literal>          | <interval literal>     <signed numeric literal> ::=          [ <sign> ] <unsigned numeric literal>     <unsigned numeric literal> ::= <exact numeric literal>          | <approximate numeric literal>     <exact numeric literal> ::= <unsigned integer> [ <period> [ <unsigned integer> ] ]          | <period> <unsigned integer>     <unsigned integer> ::= <digit>...     <character string literal> ::=          [ <introducer><character set specification> ]          <quote> [ <character representation>... ] <quote> [ { <separator>... <quote> [ <character representation>... ] <quote> }... ]

因为

<quote>

仅包含在

<bit string literal>

，，

<hex string literal>

…中，但不包含在数字文字中。