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。
