NEW YORK (AP) _ Dow Jones & Co. Inc., publisher of the Wall Street Journal, reported Monday it had slightly higher earnings for the second quarter despite a drop in revenue for its business publications.

The company attributed the decline in its publications unit to decreased financial advertising following last October's stock market crash.

Net income for the three months ended June 30, was $49.5 million compared with $49.1 million in the year-ago period, the company reported. Earnings per share of 51 cents remained unchanged.

Overall revenue rose 32.2 percent to $413.8 million from $313.05 million, while revenue for the company's business publications segment declined 8.2 percent to $201 million from $218.9 million, the company said.

Operating income, up 27.5 percent for the company as a whole in the second period, fell 31.2 percent in its financial publications unit.

The company said its quarterly revenue increase was due largely to the consolidation of the financial results of Telerate Inc., an electronic information system, into Dow Jones, which owns 56 percent.

Profits for the first half of 1988 increased 32.2 percent to $153.1 million, or $1.59 a share, from $115.8 million, or $1.20 a share, from the same 1987 period.

The company said first-half profits included a one-time after-tax gain of $64.5 million, or 67 cents a share, from the February sale of the company's book-publishing subsidiary, Richard D. Irwin Inc. Dow Jones said it had recorded an after-tax gain of $29.4 million, or 30 cents a share, from the sale of its interest in South China Morning Post Ltd. in the first half of 1987.

Dow Jones also publishes Barron's, the Far Eastern Economic Review, among other publications.