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Re: Sql: *JoinRef [message #34971 is a reply to message #34969]

Thu, 22 December 2011 08:17

mirek
Messages: 13984
Registered: November 2005

Ultimate Member

Didier wrote on Wed, 21 December 2011 18:22

Hi,

What syntax can I use to serialize more than one join at a time.

Take the following stupid .sch example:

TABLE_(TABLE_B)
	INT_    (B_ID) PRIMARY_KEY AUTO_INCREMENT
	INT_    (AGE)
END_TABLE

TABLE_(TABLE_C)
	INT_    (C_ID) PRIMARY_KEY AUTO_INCREMENT
	INT_    (WEIGTH)
END_TABLE

TABLE_(TABLE_A)
	INT_    (A_ID) PRIMARY_KEY AUTO_INCREMENT
	INT_    (A_REF_B) REFERENCES(TABLE_B)
	INT_    (A_REF_C) REFERENCES(TABLE_C)
	INT_    (A_SIZE)
END_TABLE

I would like to write something like:

Sql * Select(myData).From(TABLE_A)
      .LeftJoinRef(TABLE_B).Where(AGE == xxxx)
      .LeftJoinRef(TABLE_C).Where(WEIGHT == yyyy)

Is this possible ??

This one no. The answer depends on what kind of SQL do you want to produce.

I think the most sense makes this:

Sql * Select(myData).From(TABLE_A)
      .LeftJoinRef(TABLE_B).On(AGE == xxxx)
      .LeftJoinRef(TABLE_C).On(WEIGHT == yyyy)

(but it is not 'where', because we have left joins, so AGE or WEIGHT would yield null, which would exclude such records when placed in where).

Mirek

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