postgresql - 为什么在 postgreSQL 中使用 case 和数组函数会出现语法错误？

Question

我是 postgreSQL 数据库的新手，你能解释一下为什么我会出现语法错误吗？我在文档中找不到任何答案 docs

  CREATE OR REPLACE FUNCTION validation(string_to_match varchar [], pattern 
    varchar , validation_type varchar) RETURNS boolean AS $$  
    DECLARE a_length ALIAS FOR $1;
    DECLARE result_validation ALIAS FOR $2;
    BEGIN

    CASE validation_type
      WHEN 'login' THEN array_length (string_to_match , 1) INTO $1 RAISE NOTICE 
    'Array length is %', $1; 
      WHEN 'register' THEN array_length(string_to_match,1) INTO $1 RAISE NOTICE 
    'Array length is %', $1;
      WHEN 'contact' THEN array_length(string_to_match,1) INTO $1 RAISE NOTICE 
    'Array length is %', $1;
    END CASE; 

    END;    
    $$ lANGUAGE plpgsql;

ERROR: syntax error at or near "array_length" LINE 7: WHEN 'login' THEN array_length (string_to_match , 1) INTO... ^ SQL state: 42601 Character: 258

Answer 1

可能你想要这样的东西(？):

CREATE OR REPLACE FUNCTION validation(string_to_match varchar [], pattern 
varchar , validation_type varchar) 
RETURNS boolean 
AS $$  
DECLARE a_length INT;
BEGIN

    IF validation_type =  'login' THEN
        a_length := array_length(string_to_match , 1); 
        RAISE NOTICE 'Array length is %', a_length; 
    ELSIF validation_type = 'register' THEN 
        a_length := array_length(string_to_match , 1); 
        RAISE NOTICE 'Array length is %', a_length; 
    ELSIF validation_type =  'contact' THEN 
        a_length := array_length(string_to_match , 1); 
        RAISE NOTICE 'Array length is %', a_length; 
    END IF; 

    RETURN true; -- or false ? 
END;    
$$ lANGUAGE plpgsql;