H2數據庫CREATE TABLE與約束

Question

我有兩個SQL語句：

CREATE TABLE legs(legid INT PRIMARY KEY AUTO_INCREMENT NOT NULL, 
        playerid1 INT NOT NULL REFERENCES players(playerid), 
        playerid2 INT NOT NULL REFERENCES players(playerid), 
        added TIMESTAMP AS CURRENT_TIMESTAMP NOT NULL); 

ALTER TABLE legs ADD CONSTRAINT distinct_players CHECK(playerid1 <> playerid2); 

我99％肯定，我應該能夠將它們凝結成一個，即：

CREATE TABLE table(... 
        playerid2 INT NOT NULL REFERENCES players(playerid) CHECK(playerid1 <> playerid2), 
        ...); 

不過，我始終得到語法錯誤。 AFAIK，這是約束應該在的地方。

Answer 1

CREATE TABLE legs(legid INT PRIMARY KEY AUTO_INCREMENT NOT NULL, 
        playerid1 INT NOT NULL REFERENCES players(playerid), 
        playerid2 INT NOT NULL REFERENCES players(playerid), 
        added TIMESTAMP AS CURRENT_TIMESTAMP NOT NULL, 
        CHECK (playerid1 <> playerid2));